Positive reinforcement is a technique used to train animals where positive (desirable) behaviours are rewarded while negative (undesirable) behaviours are ignored. It eliminates the need for punishment which is never pleasant - for anyone involved - and makes use of the fact that we want to impress and please each other.
If you can get past the fact that it was designed for animals, it's a very useful technique to apply with children and colleagues. All you have to do is pick a few behaviours you want to see more of and praise or thank people when you notice them. Very quickly they will pick up on what gets your attention and praise and they will do more of it - and then you pick a few more . Little by little you can change entire cultures that way.
Do you know who else it's useful for? Yourself. By focusing on a few things at a time you are increasing your chances of succeeding; by giving yourself permission to ignore your undesirable behaviours (the ones you wished you had been able to control) you don't have to think too hard about how you failed; and by rewarding your little wins you will create a positive mindset with room to experiment and innovate.