How to Adjust a Non Stretch Pattern for Stretch Fabric Workbook. Step by step instructions to adjust basic non stretch shirt, pants and skirt patterns for stretch fabric. It’s easy to over estimate how much stretch your fabric has, I’ll explain how to check your fabric for stretch and things to look for that may be signs that you’re stretching your fabric too far. Then I’ll show you how to draw guideline on your pattern pieces and adjust them one section at a time. There are instructions showing how to adjust a basic pattern with a bust dart into a pattern with princess seams. This workbook addresses both crossgrain and vertical stretch.