My DD is very perceptive and tuned in to people's feelings - so when she was that age I found that what worked with her was telling her how it made me feel when she broke something of mine..."Mummy has had that for a long time and now it's broken! That makes me really sad!" - because she really responds to how others feel that worked well without "guilting" her ( which it sounds like you're trying to avoid?)

DS is a whole new kettle of fish though. While he does have a sensitive side to his nature its not as easy to appeal to as DD..because he's a boy he's loud and likes to wreck stuff and really doesn't think before or after he does it.

My point being that you need to work out what motivates your little one and work with that