If you get fearful, please stop as you are not ready for astral projection. Anything done in metaphysics should feel comfortable and easy. If it is stressful, let it go for now, as you are not ready.

Silva Mind Control Method
http://www.silvamethod.com/
Quiet your mind. Clear your thoughts.
In your mind say:
"I'm going to count down from 3 to 1, visualizing each number on a white orb suspended in the air above my head. When I reach the third and final "1" my body will be deeply relaxed. I will have no awareness of physical sensations. I will not perceive any physical discomfort. My consciousness will be focused on my astral body.
Now visualize a white orb suspended in the air above your head. Mentally focus on the orb I visualize a number "3" on the face of the orb. The numbers can be any color. They may vary with each experience. Visualize the 3 --three times: three number "3's" on the orb.
Your body is completely relaxed. You are losing awareness of your physical body.
Then repeat the visualization with three number "2's." You are into greater relaxation. Now visualize the "1's." You are losing awareness of physical sensations. Your consciousness will be in your astral body.
Repeat this using the number "1's" three times. Your consciousness is now in my astral body.
This could involve training of several sessions. You may also find audio tapes that take you down into these altered states as well. You getting better and faster as you go along each time.
There is no set agenda for how often you practice astral projection or any other out-of-body technique. It soon becomes fun. It is like a deep meditation.
Now the key is to remain conscious while my body is asleep. Different thoughts may pull you from your focus as the mind loves to chatter. Just push these thoughts away.

The Monroe Technique - by Robert Monroe.
Visit www.monroeinstitute.com for books, videos, and info. Note from Heather - I have read Monroe's books and they are great. I really recommend them if you are interested in astral travel.
Step One:
Relax the body. According to Monroe, "The ability to relax is the first prerequisite, perhaps even the first step itself" to having an OBE. (Out of Body Experience). This includes both physical and mental relaxation. Monroe does not suggest a method of attaining this relaxation, although progressive muscle relaxation, coupled with deep breathing exercises (inhale 1, exhale 2, inhale 3... until about 50 or 100) are known to work well.
Step Two:
Enter the state bordering sleep. This is known as the hypnogogic state. Once again, Monroe doesn't recommend any method of doing this. One way is to hold your forearm up, while keeping your upper arm on the bed, or ground. As you start to fall asleep, your arm will fall, and you will awaken again. With practice you can learn to control the hypnogogic state without using your arm.
Another method is to concentrate on an object. When other images start to enter your thoughts, you have entered the hypnogogic state. Passively watch these images. This will also help you maintain this state of near-sleep. Monroe calls this Condition A.
Step Three:
Deepen this state. Begin to clear your mind. Observe your field of vision through your closed eyelids at the blackness in front of your. After a while you may start to notice light patterns. These are simply neural discharges. They have no specific effect. Ignore them. When they cease, one has entered what Monroe calls Condition B. From here, one must enter an even deeper state of relaxation which Monroe calls Condition C-- a state of such relaxation that you lose all awareness of the body and sensory stimulation. You are almost in a void in which your only source of stimulation will be your own thoughts.
The ideal state for leaving your body is Condition D. This is Condition C when it is voluntarily induced from a rested and refreshed condition and is not the effect of normal fatigue. To achieve Condition D, Monroe suggests that you practice entering it in the morning just as you are getting up, or after a short nap.
Step Four:
Enter a state of Vibration. This is the most important part of the technique, and also the most vague.
Many projectors have noted these vibrations at the onset of projection. They can be experienced as a mild tingling, or as if electricity is being shot through the body. Their cause is a mystery. It may actually be the astral body trying to leave the physical body.
For entering into the vibrational state, he offers the following directions:
1. Remove all jewellery or other items that might be touching your skin.
2. Darken the room so that no light can be seen through your eyelids, but do not shut out all light.
3. Lie down with your body along a north-south axis, with your head pointed toward magnetic north.
4. Loosen all clothing, but keep covered so that you are slightly warmer than what might normally be comfortable.
5. Be sure you are in a location where, and at a time when, there will be absolutely no noise to disturb you.
6. Enter a state of relaxation.
7. Give yourself the mental suggestion that your will remember all that occurs during the upcoming session that will be beneficial to your well being. Repeat this five times.
8. As your breathe, concentrate on the void in front of you.
9. Select a point a foot away from your forehead, then change your point of mental reference to six feet.
10. Turn the point 90 degrees upward by drawing an imaginary line parallel to your body axis up above you head. Focus there and reach out for the vibrations at that point and bring them back into your body.
Even if you don't know what these vibrations are, you will know when you have achieved contact with them.
Step Five:
Learn to control the vibrational state. Practice controlling them by mentally pushing them into your head, down to your toes, making them surge throughout your entire body, and producing vibrational waves from head to foot. To produce this wave effect, concentrate on the vibrations and mentally push a wave out of your head and guide it down your body. Practice this until you can induce these waves on command. Once you have control of the vibrational state, you are ready to leave the body.
Step Six:
Begin with a partial separation. The key here is thought control. Keep your mind firmly focused on the idea of leaving the body. Do not let it wander. Stray thoughts might cause you to lose control of the state.
Now having entered the vibrational state, begin exploring the OBE by releasing a hand or a foot of the "second body". Monroe suggests that you extend a limb until it comes in contact with a familiar object, such as a wall near your bed. Then push it through the object. Return the limb by placing it back in coincidence with the physical one, decrease the vibrational rate, and then terminate the experiment. Lie quietly until you have fully returned to normal. This exercise will prepare you for full separation.
Step Seven:
Dissociate yourself from the body. Monroe suggests two methods for this. One method is to lift out of the body. To do this, think about getting lighter and lighter after entering the vibrational state. Think about how nice it would be to float upward. Keep this thought in mind at all costs and let no extraneous thoughts interrupt it. An OBE will occur naturally at this point.
Another method is the "Rotation Method" or "roll-out" technique. When you have achieved the vibrational state, try to roll over as if you were turning over in bed. Do not attempt to roll over physically. Try to twist your body from the top and virtually roll over into your second body right out of your physical self. At this point, you will be out of the body, but next to it. Think of floating upward, and you should find yourself floating above the body.

Astral Travel Spell
"Syn, good Goddess of Locks and Doors, Open the Gates I now Implore.
Allow me to pass through the Astral veil; with speed, Grant fair winds to me sail.
And when I've gained what I can learn, Roman Grant a hasty return"
Say this before Astral projection! I personally enjoy this one it really helps when I am trying to have an out of body experience. Most of the people would agree with me to use a meditation before some invocations to the Gods and Goddesses. I would personally recommend it very much, because meditation allows you to float in the magical world, where you can make spells, pray, as well as meeting new friends from the other world.

The Gazing Technique - (better one to try)
This is to be done when going to bed. You need something to focus on; if it is in view the moon, the stars, a crystal, a favorite doll will work well. Use whatever you like. This method involves the body falling asleep, and you should never leave anything that burns unattended. Place the object within your view and lie down in your bed. Just stare at the object as you doze off. The first few times may be frustrating. You may just fall asleep and that's it. Keep staring at the object. As your eyelids become heavy, keep staring. Eventually your eyes will close, but you will still be able to see the object. You will still be staring at the object. Sit up or stand up, and don't be surprised to see your physical body sleeping peacefully in your bed! When you are out of your body, do whatever you wish.

Vision Quest for Past Lives
1 white candle
a glass bowl filled with scented flower petals
a bed
At night time, or whenever you have peace and quiet, with no disturbance from others, light the candle, and place it next to the bowl of petals. Lie on the bed, close your eyes, and think back to when you were little, then go further and further, until you slowly remember how you felt when you were inside your mother's womb. Then slowly go further, and remember how you flew through the tunnel of light from the heaven, and back again to Earth. See your silver cord (the cord which attached you to your past life's body) re-heal, and you are back into the person's body in the coffin, or even perhaps, into the ashes, which then reunite to form your past life's body again. Slowly, when your unconscious state takes over, you'll remember who you were in your past life - maybe not right away, but you should eventually see yourself, or remember your name or those you loved. Remember, this can take a lot of practice and a lot of patience. Don't do it if you are unwilling to devote at least one hour to it.

Thoughtforms and Spirits
Whenever we concentrate our thoughts, we draw psychic energy together. This is called a thoughtform. Usually the energy dissipates as soon as we break the concentration, but it is possible to purposely concentrate energy in this way, producing very strong thoughtforms. Such thoughtforms are vortexes or centers of psychic energy. They can exist as entities by themselves, at least for a while. They are basically inanimate, non-thinking forces. Talking to one is about as logical as talking to a chair. In this way, thoughtforms are similar to elementals, ghosts, and spirits. All of these psychic entities consist of a psychic energy vortex which could be described as a localized field or as a discontinuity of the physical world. Psychic entities respond to certain electrostatic and magnetic fields, and to other energy vortexes. That is why they respond to Magick ritual. Psychic entities are sometimes able to affect our thought processes. Thoughtforms and elementals, are usually not very smart. If they display any intelligence at all, it is limited. They are the morons of the spirit world. Their behavior is usually automatic, repetitive, robot-like (just like some people). We see that artificial elementals are little more than astral robots. Spirits and deities are more intelligent and volitional.
Directed Attention
Your mind follows your attention. Wherever you direct your attention, there will your thoughts go too. By directing attention to a specific place or purpose you focus mental energy upon it.
For example: you're having lunch in a cafeteria crowded with people. It is a large place, and everyone there is talking at once, so that the room is a constant jumble of noise. You happen to notice a man across the room; he reminds you of someone. All at once he drops his fork and you hear it hit the table. But would you have noticed the sound of his fork if you had not been looking? No. Only by focusing your attention there were you able to pick out that individual event and associated sound.
It is a dark night. You are walking and the only light you have is from the flashlight you hold in your hand. As you move the flashlight around, the beam of light from it directs your attention first one way then another. Now, the mind is something like that flashlight in the dark. And by directed attention, you point the mind to one place or another. As with that flashlight beam, you see where the mind is pointed; nothing more. The rest is 'noise'. And so we could define mental noise as anything not focused upon. In another way, noise could be considered as negative emotions, attitudes, and thoughts which make it more difficult to direct the attention. Your emotions follow your thoughts quite easily. Your emotions are not you, but are rather reactions prompted by your model and ego -- like a performance or an act, while the real you watches. In a similar way, directing your attention toward a specific emotion will cause you to experience that emotion.

Source: http://www.everythingunderthemoon.net/index.html