There's been some great advice already given here! I only have a couple of things to add:
1. Learning to get just the right tension may take a little bit of playing, but it is important to know how to do that for your machine. (I'd always write down my starting tension before playing with it, in case I get befuddled I can always go back to where I started!) Don't be surprised if a different fabric or thread requires an adjustment in tension; that is normal, there really is no one setting that will always be right for every FMQ situation.
2. Don't be afraid to try (or toss out) any of our helpful advice; what works for one may or may not work for another, so if you can't get it to 'work' for you don't worry about trying something else. I have two machines I FMQ on - same brand, but one is fussier than all get out and the other one will take anything you throw at her with a smile - go figure!
The absolutely only thing that is guaranteed to improve FMQ is...more FMQ! I keep a stack of batting squares and practice squares so that I can play with it even when I don't have much time. I think we're set on placemats and coasters for a while :lol: :lol: