The typical starting point is meditation. You really have to master meditation before you can get any profound experiences with astral travel.
We have discussed this before in the Forum, check out this topic: I want to try astral projection for the first time---Any tips?
For a simple technique, try this:
- Lay in bed in a position where you can fully relax. Close your eyes, scan your body for tension and relax more.
- Either empty your mind completely, or focus on one thing (such as a mantra, sound, breath).
- If you can manage to keep this concentration for a few minutes, you will feel a vibration or buzz. It can be scary and it requires many attempts.
- Your experience from here may vary, including falling asleep, waking sleep paralysis, lucid dreaming, etc.
As mentioned above, there are many guided meditations in Youtube which can help as a starting point. Check out the link I added above too.