I am very new to quilting. I've been trying to learn to machine quilt. How do you make sure that you don't get puckers either on the backing or in the front? I lay my backing on the tile floor and then tape it to the floor. I baste my quilt sandwich with basting safety pins. I'm doing some very basic quilting...outlining a square. I use a walking foot for that. I tried free motion quilting and the backing puckered even worse. I start in the middle & work my way out to the sides. Any hints for a newbie?