I read years ago about a 'trust meter' or a something similar (sorry I've forgotten the exact name for it). The basic idea is that all relationships (business, personal etc) starts at zero and depending on the things they do or say either destroys people (-1) trust or build people trust (+1).

If you've done something negative, acknowledge it to yourself and any anyone else that was impacted by it and move forward from it. Knowing your flaws, acknowledging them and working around them is an important thing to do. 'Water under the bridge' and all of that...