Are you going to cover little square pillows or the sleeping pillows? If it's little square ones I would make a square the size you want,quilt it and then instead of binding,I would take 2 pieces of backing material (each about 2/3 size of the real square) finish one edge on each. You would then overlap the finished edges until the two fit the quilted front,sew completely around it, trim edges and corners, flip and insert your pillow form.
If on the other hand you want to fit the sleeping pillow you would put enough blocks together to fit the appropriate pillow,quilt and then either do as above or use 1 piece backing and procede to make an envelope(& you will have to bind one edge)
Of course this is the simple version, I didn't put in about cording,ruffles or "extras".
Just old fashioned home ec.