I have done very little FMQ so far, as it also scares me. After the holidays, I plan to take a few weeks where I just do practice FMQ every day for 15-30 minutes (that is if I can get the time to sit and sew daily). I wasn't ready when a group that I follow on my blog did it earlier this year.
I plan to use practice sandwiches that will probably end up being donated to the animal shelter as pet mats once completed - but some will also go into a binder of samples.
I purchased the batting sampler pack from Harriet Hargrave to practice on so that I can figure out which battings I like and also how different battings handle.
I did find when I was testing tension for a project I finished this summer that FMQ on a small piece is very different from manhandling the larger quilt, so I had to put together a larger practice sandwich.
Cheers, K