For the most part, I find we're all much happier when I don't yell. It definitely DOES NOT work for getting compliance with instructions, rules, etc. It does sometimes work for getting attention, as when somebody is wandering toward the street, or about to run over their sister with a tricycle.
Have you seen Scream-Free Parenting? Helped me a lot. It doesn't have simple easy-to-follow rules. It does help you get some perspective on yelling. Making the commitment not to yell was the biggest step. The changes were gradual, but the dds really do listen to me more now, (even if they don't choose to do what I want, they know what I said and that they are going against it) and though it wasn't my goal, I feel much better and spend much less time feeling cranky and angry and ignored.