Try it for an entire day, then an entire week. No excuses! If someone asks you to do something you don't want to do, just say, "no thank you." Don't follow it up with a reason or justification, true or not. Just say, "I'd rather not," or some derivation of that. Also, don't rescue anyone else by offering excuses or justifications for their actions or inactions. Let them own their communication and experience. Notice how it feels and where it leads. Your goal is honest, authentic communication. This is practice for dealing with what's true.