I agree with everyone else here...practice, practice, and practice some more!
If I had anything to add it would be to make sure you "press down firmly" with your hands while FMQ'ing as this gives you more control.
FYI, GLAD brand Press n Seal is amazing stuff! I would recommend that you use a marker that is similar in color to your chosen thread for the following idea, since I used a red permanent marker and could see a VERY faint...I repeat, VERY faint pink tint in a few places, so maybe use Crayola washable markers or something similar?
I printed out a motif I wanted to use, laid a clear cutting board from the dollar store over it, taped it down over the printed motif, then smoothed a piece of Glad Press n Seal over it and used a marker to trace the motif. Pull it off the cutting board and smooth it onto your block and stitch over it, then tear it off! I don't use this all the time, in fact I just recently used it for the first time on a quilt that was making me nuts. It works, AND it produces fantastic results! lol It also doesn't move until you pull it off, and you can do more than one block at a time and it's still in place no matter how much you move the quilt around.