Now this is how I make sure the sewing lines line up. I poke pins into the lines of the two pieces - corners especially - then
add the pins to hold while sewing and take out the poked ones. Sew the seam
Remove the paper of the seam allowances of the seam just made so you can iron the seams open. Saves bulk here.
Oops, added #10 first. (This is how I get into trouble... I can't count.) Now adding #9
Hope this helps you all to paper piece. It really is like paint by numbers, except it's best to keep in chronological order.
Any questions - leave a comment or email me. I'll help as much as I can.