My machine sits onto of a table - if yours does too your stich will drag. I was able to help my quilts two different way - each has worked for me, but I needed two different things because I sew in two different houses. 1st is I set up my ironing board lever with my machine (not the table), this way I didn't have the quilt draging on the floor and everything was much more even (stitches). 2nd machine on table top over to right - then I used phone books (you know ALL of the extra ones they deliver ALL the time), they come in different sizes so it might take a little working out, but it was a NO cost fix.
Good luch and happy sewing
Snooks