I can tell you what I learned in medical school about communicating with patients. We learned the stages of change model. Basically, for someone to make a change, it doesn't work to tell them to change and then walk away. That's actually a great way to make them discouraged and not change anything at all or want to come back to see you ever again. People make changes slowly. Most of the research in this was done with smoking cessation counseling, and the phases are:

Precontemplation
Contemplation
Preparation
Action
Maintance

The idea is to figure out where the patient/client is, and go from there. You can generally help someone go one step. So if a person hasn't considered smoking cessation, you don't tell them to quit. You ask if they would think about quitting, point out some of the health risks in a non-judgemental way. If a person is thinking about quitting, you can then help them create a plan. Even then, you don't give them a pre-printed generic plan. You help them figure out a specific, personal plan.

That's what I was taught in the classroom on a few specific occasions and have rarely seen used in practice. What I was taught by observation in most cases was generic advice being handed out without a current understanding of what the patient actually is or isn't doing. And then behind the scenes, an awful lot of judgement and ridicule.