Sounds like you are starting out right by doing small quilts first. Twin is the size you should try next, so go for it, be brave. Always start in the middle and move toward the edges. I do free motion. Drop the feed dogs and use the darning foot. Another thing I always do it a practice piece. I layer up some extra blocks or just some ugly or plain fabric and practice on it first so I get the feel of the quilting design first. For example I wanted to do grass and I practiced that motion before I did it on my real quilt. Have fun, every quilt is a learning experience.