I would invest in a book that covers all the ins and outs of quilting. It will give you a good foundation to start with.
Also, look at the tips page on this forum for some good information. One thing that I have learned recently (and I have been quilting for a few years, and have made a good 2 handsful of quilts) is the use of starch. I never used to use it too much, but as I have used it more, my results have been better. I also , as cjsews said, pay more attention to my 1/4 inch seam allowance.
Enjoy, don't be too hard on yourself, and keep learning. Gina