[header] How to stop on roller skates [title] Use your knee pad to stop. [step] Since it is typically recommended to wear safety gear when you are skating, you should have knees pads on already. To perform this stop, slowly lower one knee to the ground and allow it to drag. 
This is a good stopping technique for beginners as it takes very little skill to perform. You don't want to rely on it, just use it as a backup when necessary.