everyone has basically sumed it up in a nutshell.
Bring something to drink, gum, cologne or perfume etc
Don't overthink things.
If you ever feel like your tripping out and losing the realms of reality then find something to concentrate on that will get you focused. This works well.
I especially love smoking outside and being outside high its liberating to me.
And properly inhale, and if you dont feel so high from your first time, then give it a couple more tries as you may not have been inhaling correctly. Most people don't initially.
Don't smoke more than you can handle either.
enjoy:D