Be sure you're putting the walking foot on exactly right--needle in the right position, presser foot in right position, being sure walking foot is centered so your needle goes through OK and straight through the hole. Lots of things to watch but pay attention to each step, and though it seems hard at first, you will eventually get it and find it hard to imagine you ever did without it. It's such a useful thing to have--that's why the high-end machines are starting to have it built into their newer models.