If the patch has been cut properly, it should fall naturally into place when applied to the garment evenly. However, sometimes there can be some bumps in your fabric or on top of your jeans that can cause this issue. If you find the patch is not lying correctly, it is possible to lift the jeans and lay them flat. Then, re-sew your patch into place. Try lifting the jeans again if it is still not sitting evenly. It can also be a good idea to use some tape and mark where the hole will go to make sure that your patch will sit straight before you sew on it. It is also a good idea to make sure that the patch is not so large that it puts too much stress on the jeans. Too large a patch can cause issues such as uneven edges or changes in fit. Therefore, measure your patch before you sew it on!