Look at some quilting on quilts in shows. I did and I am not near as hard on myself now. The ones that are perfect are usually done with a computerized quilter.
There are videos on YouTube also. I ordered some DVDs on Feathers and am looking for that right piece of fabric for a wholecloth design. (may have to dye it myself)
I do donation quilts and get a lot of practice that way.
I have a client that only wants stitch in the ditch on her quilts and that gets boring fast.
Unless the customer requests it I always use a neutral thread or match colors so the quilting design does not distract from the quilt pattern.