Please check out this great post on the Fast Company blog about the power of starting new behavior, rather than trying to stop old behavior. Here’s a snippet:

One place this idea can be important is in changing one’s management style. Often I have clients who are abrasive with staff members and want to change how they interact. One in particular admitted that he really hated his own behavior. He then asked for my advice on how to stop it. I said, "Before we try to stop your current behavior, let me ask you one question – what do you want to start doing instead?" He looked at me blankly and said, "I’m not really sure." "That’s the problem," I said, "Let’s start there."

Do read the rest of the post. It’s clear, short, and spot on.

I think there is room for "stopping" too, but usually in the case of stopping things that you weren’t really conscious of in the first place (I recommend having a "stop doing" list in addition to your "to do" list in order to manage time and priorities). But that usually means stopping things that you kind of like doing, rather than the things you already know you need to change.