Mark the hole: Use the little chalk piece in the patch kit (if it came with one) or a pen to mark the hole so you don't lose track of it. But, don't mark the actual hole because the glue may hide the marks, which means you might lose track of the hole. To prevent this, place marks on either side of the hole about an inch away (photo). Alternatively, simply tear the hole slightly larger (about 1/4 inch in diameter). Don't worry, the patch will make the tube good as new.

Tip: Be gentle when marking the tube by tearing, especially on lightweight tubes, which are fragile.