I got vinyl sheets off cubesmith since I had already bought a bunch of stickers from them in the past. I just tried taking an old sticker and sticking it to the vinyl as a template but when I cut it with scissors it came out totally off. Then I tried doing it with a razor blade and it took longer than I would like, although it did come out looking cleaner than the first run.

Thoughts?

When I cut my own stickers I draw them accurately as outlines using Visio (but I guess any computer drawing package would do) including the rounded corners. Then I print them off as complete faces, and stick the printouts (using spray glue) onto the back of the vinyl sheets (so take care about non-symmetrical stickers). Using these, it is easy to cut out the stickers using a straightedge and sharp knife. To get the rounded corners, I use those craft scissors which can cut curvy/wavy edges. (But using Oliver's Stickers is easier )

Tony discusses hand cus sticker methods here. Spend some time reading Puzzle Building and Modding and you will pick up all sorts of good hints. The further back you read, the more you will learn

Dave

In your situation I would suggest holding the sticker on the back of the vinyl (assuming it has a peel off paper back), draw round it and then use a steel ruler and small craft knife (not scissors!) on a flat smooth surface (which will get cut up) to cut it out. Do it carefully and slowly. Don't worry about rounded corners until you have cut out the stickers, then just cut the extreme corners off.