For starters only be around people you know and like. Some people like less shrooms, others (like me) like more. Start with a lower dose to be on the safe side. And don't start worrying you're going to stay tripping permanently-a very common, silly thing to believe.
Shrooms, as with all psychedelics are harmless, a lot of fun, but powerful. Once you have tripped a few times your confidence will increase, allowing you to experiment with more (the more you take the better it gets in my opinion). Enjoy