One way to improve your odds of astral traveling is to work on your astral travel techniques. Sometimes our subconscious is preventing us from astral projecting because of a recent increase in stress levels or unpleasant experiences. If this is the case, you need to remove all your fears and convince yourself that you can and will astral travel.
If your last astral experience was not as pleasant as it should have been, try to remind yourself that nothing can happen to you in the astral plane. You may come across negative entities at times, but all you have to do is wish to avoid them and your astral body will. They are easy to spot because of a negative energy field around them. Avoid anyone with dark auras.
If you have other fears (perhaps unconscious fears), you will not be able to astral travel (OBE).
Another option is to "protect" yourself before you leave your body. You can place salt at the north, south, east and west corners of the area from which you normally leave your body. For example, you could put a little pile of salt next to each leg of your bed if this is where you normally astral project from.
You can also request that your astral guide be there to help you throughout your OBE. Most people believe that astral guides are with you at all times when you are on the astral plane. The purpose of astral guides is to help you with self improvement and self awareness while on the astral plane. They can help you reach the next realm if you so desire.
Sometimes, OBE can't happen because of the way we express ourselves. Talking to our friends about our OBEs shouldn't affect our abilities at all, unless we keep reaffirming that we can't have OBEs anymore... If you keep repeating something aloud, no matter how true or wrong, your subconscious starts to believe it. Call it visualization if you wish, it's kind of what athletes do in their mind to physically improve their performance. It has been proven to work.
So here is what I recommend you do to improve your astral travel techniques:
Start keeping a journal to record all your OBE experiences (or current lack of) and document which techniques you are using. In this journal, on the first page, write down a list of reasons why you want to have OBEs. The more positive and selfless reasons, the better.
Try to align your body with the imaginary line that joins the south and north pole with your head pointing north.
Try a new way to astral project. I recommend you start by lying down in a comfortable position and repeat (mentally) that tonight you will have an OBE. Keep breathing in and out while repeating it. Slowly and gradually tense and relax all your muscles, starting with your feet all the way up to your face, and keep affirming that you will be successful with your astral travel techniques. If you fall asleep without anything happening, don't worry about it. Simply record how far along you got in your journal and be proud of your achievements.
The following night, aim just a little higher, perhaps try to feel the vibrations before the astral body detaches from the physical body. Keep taking small steps, if you do achieve separation, stick to your room for the first night.
Anytime you get a chance, think positively about your small successes and possibilities, and record everything in your journal.
When you do achieve separation for the second and third time go ahead and explore the astral realms. Your astral travel techniques will improve with each astral experience.
Try to meditate before astral travelling.
Work on your chakras. Perhaps you are experiencing a "blockage" on the emotional level or some other level.