Getting on the astral plain can be very easy, or very hard. It varies from person to person. Some can simply meditate and go onto the astral plane, others fall asleep first before they go there.
If you want to try astral projecting, you really should lucid dream first. By lucid dreaming you can learn to control your dream state, remember, you are always in control. Once you've mastered lucid dreaming, then and only then should you try astral projecting.