If you live in a state that doesn't have regulated access, or you simply want to work with someone outside of a legal model, here's a tip on how to find a guide: start attending local psychedelic events put on by your local psychedelic society or meetup group, or go to academic events or pscyhedelic author readings. Make friends, and go slow. Don't trust everyone right off the bat -- take time to get know people.
Let your new friends know you are looking for a psychedelic practioner to support you. Get specific about what you want help with (e.g., microdose coaching, spiritual exploration through psychedelics, healing trauma or depression). Not every practioner is going to work for everyone.
There are a lot of skilled psychedelic practioners working in the underground, and there are also a lot of charlatans or people with an inaccurate sense of their skill level. Some are well-meaning, some not. Finding the right psychedelic guide for you means getting referrals, and it also means asking the right questions. Just because one person had a good experience with a practitioner, doesn't mean they are going to work well for you.
If you get connected with someone who you want to work with, please consider asking them some of the questions from Psychedelic Safety Flags.
If after asking them some of these questions you don't feel good about putting your well-being in their hands, keep looking!