Topstitching in Tight Places

Another question someone asked a while back was how to keep the topstitching neat on the Box Wallet.  For those of you with the pattern you'll know this is a tricky step and that as you come around the back side of the wallet you end up in a blind spot. 

I ran across this tip in a sewing magazine and it works great: place a piece of tape on your presser foot indicating where to line the fabric up to continue topstitching at the same length.