I started with Stitch-in-the-ditch which on occasion turned into meandering around the ditch. That was relatively easy and I realized that I really needed to pay attention to the sandwich and baste process. The backing needed to be taut (but not over-stretched). Then the batting needs to be nicely smoothed and the top too needs to be smoothed. I have had good luck with that method (both pin basting and spray basting).
Once I ventured into FMQ it was a disaster. I had plenty of books and watched videos. I took classes and while I was in the class, everything went well. Alone at home it was a different story. I told DH that I was so bad I didn't even suck at it. lol
Over time I had to give myself the proverbial kick in the pants to keep practicing. I also started to doodle and have filled many sketchbooks with doodles and FMQ patterns. Craftsy classes helped me too. My favorites are with Christina Cameli as she is so positive and supportive.
After that, it's practice - practice - practice and you'll be amazed at the progress.