Sneaky ways to stop drafts and save money

I was getting annoyed by these random cold drafts in my living room, couldn't figure out exactly where they were coming from. Ended up using a lit incense stick on a breezy day - just walked around slowly and watched the smoke. Found some pretty sneaky gaps around window frames and outlets. Sealed them up with some cheap caulking and foam gaskets, and honestly, the difference is huge. Anyone got other clever tricks for finding and fixing these hidden leaks?