It's better to say clever things than to tell people that you're clever.
These words came into my head a while ago and, ever since, I have been trying to live by them. Hopefully I already was. I think it's a good motto. I love a motto, generally.
This one applies to most things, I think. As a basic rule, it's better to do a thing than to talk about doing a thing. I believe a lot of people could learn from this.