This guide is a ever incomplete compilation of best practices for your first psychedelic trip.
LSD Psilocibin Mushrooms Guide should be useful for most psychedelic substances. https://wiki.tripsit.me/wiki/Category:Psychedelic
Low, Common or HIgh-Dose for the first time?
Is a tripsitter needed? Which person is suitable?
Tripping alone vs. in a group. Friends vs unknown people. 'Sober people'