The best thing to do is look at the experience reports on erowid.com, there's tons of reoprts on "what it's like." There is also a lot of info on doseage and set and setting. I would say a good first dose is two grams rather than one, if they are psilocybe cubensis. Other kinds have different doseages. Also, I will diagree about the advice to never trip alone. Maybe you shouldn't the first time, I did, and I prefer to be alone, but most people don't. I always get an anxious buzzy feeling right as they begin to come on, and sometimes a little nauseous. If you feel like you need to puke, and it's messing with your head, go ahead and puke...or make yourself puke if you want to. You'll feel a lot better afterwards...and uh, read the erowid section on shrooms is the best advice I can give.