The best definition of Astral Projection that I have ever read, and will always use to explain it to people is:
Astral projection is a process through which our consciousness leaves our physical body and is free to travel anywhere, unrestricted by our normal physical boundaries.
Dangers? None. There's nothing to be afraid of. In the astral, you're your own master. You are free to do whatever you want, go wherever you want to go, etc.
Benefits? Mentioned above.
Astral projection is a very interesting subject, practice and experience. But it may take a long time before you can have an OBE. Make sure to study as much as you can, believe in yourself, then start practicing.
You can try the Rope Technique, Monroe's Technique, The Thirst Technique, Astral projection via Lucid dreaming, etc. Many techniques, you can also invent your own technique.
There are hundreds if not thousands of astral projection techniques, if one doesn't work for you try another one. You may practice a technique as long as you want, but if it doesn't feel right, simply use another one.