If you want it to be really interesting, then have lots of synchronicity in there, between the astral and reality. ie ground it well in his real day to day life, make the astral relevant to living.
Interesting you mention this idea, I too am writing a story right now that has something to do with astral projection. It's really more of a story of redemption and seeking ones own identity. It's a lot harder to write than I had previusly anticipated and at times it's hard to find the motivation required to develop character, etc. but I am determined. Anyone know about publishing and how you contact them, etc? I have a few books, etc. but I would like some practical information.
fides quaerens intellectum
I had an idea to write a fairly long story about an astral projector who started out as a regular teen, then he starts to have visions in his dreams. He repeatedly encounters a man who is crying throughout the story. In the story you learn how he came about learning to project and how he finds out what the crying man(its an astral being) is. I know this sounds kinda screwy at first glance, because im typing quickly.
Its going to have heavy detail in it about Astral projection, and its also going to be a very spiritual story. Any ideas before i get started, or possibly a comment on the idea would be appreciated. Oh, and expect me to appear in your dreams sometime if anyone steals my idea. Just kidding