Hi Katara,
I've been out of the astral loop for a couple years, but I had a large amount of success over the course of about 4 years before this. Since then my focus has shifted and I haven't come back around to OBE efforts. However, my successes are notable, as I had the most trouble of anyone I've ever known in getting out of body.
So I ought to be able to give you some pointers. First, here's some things to understand/expect:
1) fear/panic - It's entirely possible that the first time you actually succeed, you will panic. It's completely natural and many people do. It's a very bizarre feeling (especially if you use a fully conscious projection) and can cause you that split second of panic that causes you to lose it. Solution: Reaffirm your desire to yourself and keep trying. After a time or three, this panic reflex goes away...
2) other fears - A lot of people have a lot of different beliefs, and these beliefs form the way that they experience their astral travel. The basic fact of the matter is that everything in the universe is one thing, one energy, and all division is merely illusion. When you project, you are not "leaving your body" really because in fact physical reality (space as well as time) do not exist - they only appear to. So not understanding the fact that you are merely altering your consciousness, many of not most people perceive of astral travel as "going somewhere". For this purpose, most people feel the need to create some form of "protection". They may have guides, angels, their higher self, astral friends, whatever you want, who help them. Many also perceive a silver cord, because it causes them to intrinsically realize that they are safe and still connected to themselves, when in fact it is impossible to be otherwise. (There is no real cord, as there is no real separation, just a shift in consciousness... actually, this is kinda hard to write in words) - take any view on it that makes you comfortable, but the bottom line is you are safe when projecting, there is no need to fear that anything can "get you", "take over your body", or that you can "get lost and not find your way back". Anyone who has vehemently argued to that effect has basically believed it into existence for themselves astrally. It was them that caused it, not something malevolent.
3) Now let's get to actually "getting out". There are three basic steps that are absolutely necessary, and the points after that will basically take care of themselves. For the best information you can find in existence (as far as I know), buy Robert Bruce's book Astral Dynamics - that's the IT book of astral ability (but also will cause enhancements in all psychic/spiritual development). Here are the most important steps, which took me sooooo long to master:
Step 1> You must must must must must must MUST be able to meditate for an extended period of time without the bother of mental chatter (ie verbal thoughts) - you can practice this any time you want, just begin to monitor your mind and place your awareness on something such as your breath. Whenever you catch yourself blabbing away again mentally, take note, release the mental chatter, and focus on your focus point again. Do this a few times each day until you have developed the ability to silence your mind. This seems daunting, but in all honesty doesn't take very long to master. Another tip that someone gave me once is a kind of shortcut to experiencing what this state feels like. Pretend as though someone has told you to "listen up, this is very important." In that split second that you stop and give your attention to someone, but before they say anything, that mental chatter has stopped. So practice "listening", in order to learn to quiet the mind.
Step 2> You absolutely must must must must MUST be able to relax your body completely. This is the step that caused me the most grief. I did not realize for the longest time that I was still slightly tense in certain areas. You must practice relaxation ad nauseum, which sucks because it is a very boring practice. It won't take long before you automate the process, so don't worry too much. At first, you will have to spend 5 minutes relaxing feet, then relaxing legs, then relaxing stomach, then chest, then arms, then neck, then face, tensing muscles, etc etc etc. It's a huge pain and can cause anxiety at first, becoming difficult to finish. This is a subconscious resistance - push past it. When you really get the hang of it (Bruce's sponging technique* seemed to work best for me, as well as a golden warm ball moving through my body), you no longer need the tedium. You will be able to lie down, tense your entire body for 4 seconds, and relax completely, immediately. Man, is THAT a happy day!
Step 3> You should, non-verbally/mentally, create some imaginary action that is in motion.** The reason is twofold - motion seems to trigger further relaxation and put the body to sleep. The other reason is that motion allows your attention to remain focused which keeps the mind awake. You will most likely know you have achieved this goal, not when you think you have, but about 20 minutes later, when you suddenly blink out of consciousness and back. You will feel your entire being expand and a deep deep warmth, at which point you will be able to remain happily in this state for hours. I used to remain in this state for hours, as a matter of fact, with absolutely no sweat off my back. Because IT FEELS AWESOME! Now, stay this way for long enough and continue an imaginary motion, and you will sweep out of your body. However, if you can keep your mind awake and focused without in any way straining your physical being, you will eventually pop out of your body anyway. That's why I listed step 3 as a "should", instead of a "must". It's just easier to do it this way - when you get good at it you won't need a "technique" so much.
* The sponging technique in a nutshell: Imagine a hand with a sponge dipping the sponge in a big bucket of water, then imagine that hand pulling the sponge up through your feet, slowly, to about your ankles. Feel your feet fill with the water. The sponge goes back in the bucket, and pulls through your feet up to your knees, again feeling the water inside your body. Continue repeating this until you have sponged all the way up your body - I find this one in particular to be highly relaxing and generate a large amount of buzzing feelings.
** My favorite and most useful, oddly enough, is imaging that my mattress is on a rollercoaster rail, going backwards. I have trouble imagining going forward on this rollercoaster, but I can easily imagine going backwards, and can imagine the scenery in front of me rushing away from me as I shoot up, down, and loop-dee-loo. I think the going backwards helps me to melt into the mattress also - surrendering yourself to gravity entirely is a very cool feeling, which accounts for the "sinking" feeling people experience. Also note that I did 95% of my meditation and astral work lying down in bed on my back, which is generally not recommended (lying in bed stimulates sleep habit), but just seems to work better for me.
Dear god I wrote a book... Hopefully my endless blabbing will have provided you with something hopeful and helpful. Good luck and happy travels!