I am a tried and true member of the churning tummy club. I have made more than a few tucks on the back of my quilts that needed attention and ripping out. So, I learn.
I am sure many on this board will tell you to practice on small samples to get the free motion "thing" down. It does help. The tucks, well it demands more. Baste a lot, or if you use pins, pin a lot but this all starts with a flat, taunt back before you even start to baste. I found this the best advise and help I have ever had with eliminating the tucks and wrinkles on the back of my quilts. I tape the back of my quilt to the floor to start my layers and then check for wrinkles after all my basting (pins) is done. I can catch some whoppers before I ever put the quilt under the needle.
Quilt in a place where you have room to spread out a large section of your quilt so you can "feel" the little bumps and tucks and smooth your fabric as you quilt.
Lastly keep trying. It does get better. I can't afford to send mine out and can no long do large quilts by hand but I am getting better at the free motion and eliminating the hours of ripping.