Well, running out of fuel works as long as your engine isn't tuned lean, but sooner or later you'll need to stop it before the end of a tank, and you have a couple of options:

1. Pinch the fuel line with your fingers or pliers until the engine dies, it'll only take a few seconds.

2. Stop the flywheel. You can give it a firm tap with your thumb (I wouldn't try this with any larger engines though, ie a .27 on a MT or anything), use the handle of a screwdriver, your shoe, a stick...

3. Flood the engine out by covering the exhaust stinger with a rag or your shoe. This forces all of the exhaust down the pressure line to the fuel tank, in turn forcing more fuel into the engine until it floods it. There is some risk though that this can break or strain your connecting rod.