You can overlap tapes. What i mean is, once u put a piece of tape down. U can take some of the backing off of it to expose the tape, Than place the tape on top of it if you have to. This makes it a lot easier to get the tapes lined up perfect up to the edge. It is ok to overlap the tapes. Just peel up some of the backing, place the tape where u need it, and than u can put back down the backing. Also if you make ur hair system a little smaller than ur balding area that helps too. Sometimes the tape overlaps ur own growing hair and doesnt attack firmly to the scalp.

Some people prefer liquid glues to get a flush/flat attachment to the scalp. Hope this helps