Know that number at all times. Track it on a chart. When you are clear about what is most important to you, it is a lot easier to shut down activities that consume your time but don't lead to where you want to go. When you are clear about what's important, it is also easier for you to ask for what you want. Don't let anything get in the way of what you say is important to you.
Clarity is the hallmark of a well-developed accountability skill.
Define your goals and priorities in a very tangible and measurable way. Use a point form, single sentence approach. Sure, you know what you want to do. Scope can be very liberating - it helps you to avoid doing someone else's job. A well-defined scope prevents you from getting in over your head or into areas that are not your responsibility.