Hmm, I quilt on a longarm, but when I first started, I quilted a lot on my domestic machine, and I used big safety pins for basting. I tape my backing down to the floor, and as I'm pinning, I have this clear square glass piece that goes to an end table in my sunroom. It helps keep the wrinkles out.
This might be obvious, but make sure to press your backing and quilt top. You'd be surprised at how many people come to get something quilted on the longarm and their back and top are crumpled up in grocery bags.
Also, if you buy packaged batting, take it out of the packaging 2-3 days before and kinda let it 'air out'. This will help release and relax the wrinkles!