I pin my layers together by first layering the sandwich together on the dining room table and hand smoothing the best I can. Then I slide the whole sandwich off one end of the table with just one corner left on the table. I start pinning there (I use Pinmoors) and carefully pin diagonally from one corner to the other as I push the fabric up from the floor. The weight of the fabric hanging over the edge of the table works to keep everything smooth. Just keep sliding the sandwich up as you pin - and I'm pretty liberal with my pinning :) Hope this helps -