blonde - if you have a walking foot, be sure to use it, that sure helps.

Also use a walking foot. That helps with the layers moving together & helps prevent the little mounds of fabric that someone mentioned.

I would do the squares first, than the stitch in the ditch.

I would SITD first to hold the quilt sandwich together, then do concentric squares in the plain blocks. You can use your machine foot as a guide for spacing.

If you are going to machine-quilt, then quilt in the ditch between 2 rows from one side to the other, then turn the quilt one-quarter turn and stitch from one side to the other, then another quarter-turn, and so on. In other words, do not stitch the quilt all in the same direction, but alternate so that half of it is stitched from top to bottom and the other half from bottom to top, half from left to right and then from right to left.

When you begin the diagonal quilting, do the same thing, alternating directions. This practice keeps the quilt from pulling on leaning to one side or the other.

The diagonal quilting will add an important design element to your quilt, as it will add a different dimension from the up-and-down of the squares.

I went to a quilt show this spring in my city and one quilter used a serpentine stitch over her seams instead of SITD and it looked so neat! it made it look really poofy, but it was flat. unfortunately my machine doent have that stich, but i have used the same technique with other stiches because my stitch wont stay in the ditch! lol

I was just about to tell you that if you had some type of serpentine stitch or another fancy stitch you can stitch that down the seam line and it is much easier than actually stitching in the ditch. I started off with in the ditch but don't do that any more, I use a fun stitch.

now just what is a serpentine stitch?

One that looks like a snake or a wave. Or think of hills and valleys, not a zig zag.