Lisa,
Bless your heart and welcome to the quilting family! I've been doing this about 15 years now and I still rip out unacceptable work. Practice is a huge part of it. I still do a practice piece on scraps before starting on my real quilt, just to get back into the rhythm. I do "guide" the fabric under my walking foot, and I do dial in a slightly longer stitch. Guiding the fabric prevents the "pulling" that causes the tight or crooked stitches. It also takes some practice to find a "throttle speed" that works best for you. My recommendation is to practice your quarter inch seam on sewing 1 1/2 inch strips together, then practicing your quilting by quilting in the ditch along the seam lines. Keep your practice piece to run a couple of lines prior to working on the real project.
Again, welcome. This is a fantastic board for experienced advice. There are a lot of articles under "articles" that may help you with some of the basic stuff.