I recently purchased on 18" mid-arm quilting machine made by ABM, an industrial sewing machine company. The machine sits on a sturdy frame and runs on large wheels - making it very easy and smooth to use. The stitches are even and it handles a wide variety of threads.
My first practice was on a sandwich of fabric that I'll use to make place mats. Here is a link:
It's not the prettiest machine ... but it works great! The design was easy to work with, the shapes are abstract and look good even if the stitching is not exact. So ... I followed the fruit and used leaves and loops in between.
My second practice was on community quilt for my guild It is a flanelette scrap lap quilt made by another guild member. I've quilted it and a third person will bind it. This will probably go to a nursing home.
I used stars and loops with an occasional butterfly thrown in.