One thing, before practicing, helped me greatly to learn FMQ over 15 years and 60+ fm quilts ago. That was watching my quilting teacher do it, having her explain it, and trying "e" and "l" loops under her watchful eye. Then I practiced, and later took more classes. One by Harriet Hargrave was especially good. What I find most necessary is the right ergonomic setup. You must be comfortable, and you must have proper support for the quilt. This means the bed of your machine must be the same height as the surrounding support table, and it is good to have plenty of room to the left (3 feet is good), 3 feet to the front, and a 2 or 3 foot support to the left side and at a right angle behind you. The gloves are also important and Machingers are great. I can take or leave the Supreme Slider.
Your job is to steer and feed the quilt. One of the most valuable things I ever learned, from Caryl Bryant Fallert, was to only be concerned with the six inches around the needle when fmq. That makes a huge difference!
Beyond that, you need a consistent foot pedal depression to hand moving speed. I prefer to run the machine faster and the fabric slower.
I suggest you practice on small things that don't matter (charity quilts?) and have a glass of wine before you start. Put on some music with a good fmq beat.