You've set priorities, broken your project into tasks, now what? Set aside time to do it. Too often, we put an item on our to-do list, fail to get around to it, and move it over to tomorrow's list. Why? Meetings, interruptions, phone calls, crises, more interruptions.
Continually shifting gears seriously diminishes productivity, especially for tasks that require generating new ideas. You need to get control of your time by creating dedicated blocks that you can devote to a specific task.
Begin by literally drawing a line around blocks of time on your calendar. Turn these into appointments with yourself. Keep these appointments as faithfully you as would any other.
The time shouldn't be less than 15 minutes or more than an hour. If you can, retreat from distractions -- maybe to a conference room. Don't take phone calls. Sit down with a goal in mind and work steadily toward it.