I have no doubt you'll get better (and feel better) as you gain experience. I just finished my first big quilt -- a kaleidoscope that I started in Feb '09. The workmanship is extremely flawed but I still like it, because of the colors. It seems like I learn one new way to improve with each project.
Surely you shouldn't be embarrassed to send your quilts out to a LAQ!
I think one thing I should be doing (but haven't so far) is to stay with a similar pattern (or one using the same techniques) so that I can get better at them before taking on some new skills. Some of the basics I've learned from this board is:
1. starch your fabric so that the cuts are very precise and the pieces don't stretch out of shape while sewing.
2. when cutting, don't skimp on the measurement -- but be consistent.
3. go as slow as you need to keep stitching straight and maintain 1/4" seams
4. use something to ensure your 1/4" seams (either a special foot or a guide you stick on your machine -- like a couple of post-its)
5. use patterns that tell you which direction to press (some don't) because it's pressing in the right direction that makes those points line up. BTW, if you've starched your fabric, finger pressing can be sufficient in many cases.
I'm sure others will be more helpful -- but don't be discouraged! Some of the quilters on this board are VERY experienced and sewing and quilting.
One last word...hand quilted finishing is even better!