Originally Posted by Metanoia
So far I think that the process is that you lay out the top, bottom and batting, and leave enough batting and bottom incase of a little shrinkage. Then the whole lot is pinned with safety pins starting from the centre out.
Yes, you sandwich those three components, but the key is that they have to be flat when you do them. I press the backing and the top prior to assembly, and I make sure that the heavy creases are out of the batting. I lay out the backing (right side down) on a large table and tack it down with a wide blue painter's tape (easily removable). Then I center the batting on the backing, making sure to pat it down smooth. (The tape will help keep the backing from shifting.) The top goes down last and it too needs to be patted out from the center to the edges.
It is a good idea to plan the quilting before pinning the sandwich, so you don't put a bunch of pins right in your line of sewing. The recommendation is to pin a distance no larger than your hand - that should be sufficient.
Stitch in the ditch (SID) is one of the easier straight-line options to quilt. You sew right down the seam line on your block. It's hard to say where the seams fall on your quilt, but you can certainly quilt down each block row in both directions. Then you can always add lines for each block.
Good luck.