The point of the 180 is to completely change your behavior, 180 degrees. You start doing the exact opposite of what you were doing.
I used to text or call STBXH, daily, with stupid questions, pleading, crying, begging, etc. Now, I rarely initiate a conversation (except for this morning, because I had to brag about beating him in Fantasy Football

), and if he sends me a text, I may or may not answer it. I usually answer his calls, but I make it a point to stay short and sweet.
The biggest thing that has helped me is the avoidance of discussing our marriage and the OW. When STBXH and I talk, she doesn't exist and our separation isn't bad for me. As a result, no arguments can ensue, and I feel like I'm in power EVERY SINGLE TIME.
As another poster said, following through is the hardest part. There are so many times I want to profess my undying love for the turd, but I know how many steps back that would push me.