Guidelines 4 Quilting makes a prep tool to get a 1/4" seam. It is a 1/4" ruler and you purchase their Seam Guides, (2" long each) which are thick and you lay the ruler next to your needle when it is down.
Then you take as many seam guides (I use 2) and lay them right next to the outside of the ruler. They are sticky on the bottom, but don't leave residue.
This outfit is awesome!!!