If you feel like you've been trying to project for a long time and seem to be getting nowhere, you may need to review your techniques and adjust accordingly.
The following are what I see as the most common mistakes people make while trying to learn to astral project. While these really aren't "mistakes" because they work for some people, they do seem to slow progress down.
1. Trying at night. If you try to project at night, especially before you go to bed, nine times out of ten, you will fall asleep. You've had a long day, your body is worn out, so how can you expect to achieve Focus 10 or Focus 12 (body asleep, mind awake)? You need to either try earlier in the afternoon, or switch to weekends when you can sleep in. If you switch to the weekends and use, for example, my technique that I wrote about under the Astral Projection link called "My Favorite Technique" then you're very relaxed and can slip back into sleep, yet the mind is refreshed and more likely to get into Focus 10. Try it and see.
2. Fear. Are you afraid you are going to die? That someone will cut your cord? You'll be possessed? Any of these fears will keep you thinking about this, and not letting yourself project. Always address your fears before expecting any results.
3. Inner dialog. Are you talking the whole time? Saying things like, "Is this right?" or "I wonder if I'm close?" To induce the vibrations, you have to have no thoughts. Your thoughts need to be narrowed down to a single thread. When you are trying to get your body asleep, stop talking to yourself and "listen". Listen to the faint ring in your head, but don't analyze it. Listen, but don't talk. When I induce the vibrations, my body has fallen asleep, the ringing has faded (because now I'm asleep), and I'm gently focusing on my third eye. All my thoughts are gone. This takes a while to master, but is necessary. Also, if you do slip off onto other thoughts, just let that happen, but gently pull your thoughts back to the single thread and keep focusing on your third eye.
4. Not understanding relaxation vs. body asleep. I get mails all the time from people saying that they are trying to astral project with their eyes open! To leave your body, you have to reduce the magnetic pull to the point that separation can occur. All things electrical create a magnetic pull. Even thinking sends out electronic pulses and creates magnetism. Pulse and heart rate also creates energy. Do not confuse "relaxation" with Focus 10. Focus 10 is Body Asleep. You have to learn how to fall asleep physically, but keep your consciousness from slipping into a dream. When the body falls asleep, everything slows down which reduces your bodies magnetic pull. Then, if you can master the "no thought" part, the vibrations will rush in. And when they do, you still have to keep your thoughts to a minimum because the excitement will increase the heart and pulse rate and then you'll be sending me mails saying that you can only raise your astral arms or legs! Most of the primary chakras are in the head and torso region which is why your head is the last to separate. So excited thoughts only make it harder. As my guide told me, "Get out of your head!" To tell if your body is asleep, you should no longer feel it, shouldn't be able to hear, and hypnogogic imagery will start appearing. Don't fight the images, just don't let them take over or you'll start to dream. Always gently bring your consciousness back to the project at hand.
5. Impatience. Conscious astral projection can take months or even years to accomplish. If you are expecting results in days or weeks, you will more than likely give up or doubt its existence. Astral projection takes discipline, dedication, and a ton of patience. It will happen, but be prepared for the long haul. It's worth the wait and effort.
These five are the top reasons, but others can include not removing distractions (kids, pets, phones, spouses), or not getting enough sleep so that when you do sleep you sleep like a log and can't keep the mind awake.
If you want more info on the "fundamental truths" to astral projection, read the article called, "The Fundamental Truths to Astral Projection