It's suggested by some tent manufacturers that the inevitable dirt getting in the zipper teeth is a cause of problems. They recommend cleaning the zipper with a damp rag frequently.

In your case, it's a case of developing the technique of keeping loose fabric away from the zipper. Practice helps. So does patience!

I have two zippers that keep causing me problems. Unfortunately, one of them is my sleeping bag zipper. It always jams when I'm in a hurry to get out of bed!