Start by working first with a little piece of a sandwich until you get your stitches right. Use the same thread on the top and bottom. Set the machine to straight stitch and sew a few stitches with your straight stitch foot with no problem. Change the foot to free motion quilting (I assume that your problem is with FMQ, since you don't say) and lower the feed dogs if your machine allows it. Stitch until you get loops at the bottom. Change the tension on the top thread little bits at a time. When I had my Brother I found that depending on the thread I used I had to sometimes increase and sometimes decrease it. Make sure you change only one thing at a time. When stitching, move your needle very fast, but move the fabric slow. If you move fast you will them get eye lashes on the top and you don't want those either.