Principles I've used outside tech...
- DRY... are there things you do regularly that you could streamline? Automating bill payments springs to mind.
- YAGNI... Are you spending lots of time on something in your life you don't really need?
- Cruft... are you keeping objects you don't need?
- Redundant backups... do you have things you rely on that have no backup? eg. you might have a gas bbq that works in a blackout (ie. when your electric stove is no use).