Lots of good feedback here.
I'm still pretty new, but my biggest change so far was training myself to own my business, not have the business own me. I stopped advertising to the general public and mostly only do B2B. The customers come to me.
I worked for a place years ago who had a decades old slogan "The customer is the boss". F that, no thanks. Like the marketing gimmick "The customer is always right", that needs to go away permanently. I'm providing a service for someone and want them to be completely happy, but the exchange is a two way street. People that don't respect my time can go elsewhere.