I'm still very much a beginner FMQer, but make lots of practice sammiches and practice just meandering to work on getting your tension right and just getting a feel for speed, stitch length, etc. Then choose a pattern to sew, and just know that initially, it's going to look bad. If you get frustrated get up and walk around or try another FMQ pattern. I bounce around to different patterns when practicing - it cuts down on the frustration and eventually you realize that each one is improving. Yeah, practice, practice, practice.
It can be fun, I promise!