Never say “no,” but rarely say “yes.”
I remember the first time I discovered this principle. There was a web project I really didn't feel like doing. A big demanding client wanted a project done in a very short amount of time. I quoted at 3x our price, and it was immediately accepted by the client. The project was successful and we did a great job.It made me realize one important, no, crucial! thing: If you're mad at your client for any reason, it only means you're not charging him enough. It's very hard to be mad at a client who's paying you a ridiculous amount of money for something you're fabulous at.