Start by doing an internet search for open mic jams in your area and ask other musicians you know if they could recommend any. When you find one you’d like to try, call the venue ahead of time to get some information about the event. (Some open mic nights may be too small to accommodate a drumset.) Find out what kind of music they play and if they accept beginners if you are less experienced. If you are underage, ask if you have to be 21 to get in. Most of them are free but also ask if there is a cover charge to get in.
The way open mic nights usually work is when you get there, you sign your name and note the instrument you play on a sign-up form. Guitarists may bring their own guitar but usually, the drummer uses the house band’s kit. (Feel free to bring your own drumsticks.) The band will start with a 30 to 45 minutes set. After a short break, they will start calling up musicians to sit in with the band in the order that they sign up. Depending on how many musicians sign up, you will usually get to perform 1 to 3 songs.
You can use the downtime when you’re not performing to listen to the other musicians play and to get a feel for how things work there. Take note of which band members give cues and how each of the musicians interact with each other. Also, take note of the songs that the band and other performers are playing. If you don’t know the songs, it may be a good idea to take the time to learn some of them before you come back to the next jam. This downtime is also a good time to meet and network with other musicians. (You’ll meet musicians with a positive attitude and some with a sour attitude. Don’t let the bitter ones get to you.)
Once you are called on stage to play, make sure that you support the music and the other musicians you play with. This isn’t the time to play all of the fills that you’ve practiced at home. There are definitely appropriate times for you to show what you can do, but you’ll impress everyone more by creating a strong pulse that makes the music feel good, regardless of how many fills you do. It is customary at open mic nights for the musicians to take turns soloing or trading four measure breaks. If you feel comfortable doing so, watch for cues from the bandleader that is directing the open mic.
Overall, have fun and be respectful of the other musicians and their gear. Think of yourself as a guest. If you try one open mic night and it’s not what you’re looking for, continue to try others. It may take some effort, but open mic nights can be a great way to improve your playing and meet other musicians.