"Your mind is not a warehouse, it's a factory." So many people (me included), tend to use their mind as a warehouse. We keep arcane facts, appointments, commitments, to-do's, worries, plans, and passions all whirling around in our heads.
We think we are more productive when we have the ability to instantly 'touch' each of these items if we need to. Unfortunately, all of these items tend to get in the way when you want to do serious work or thinking.
We tend to focus on the urgent and put the important on the back burner. And when the mental whirlwind causes you to forget something or procrastinate on an important task, your mental Jenga stack of blocks fall apart.
Stop being a warehouse — try to delegate/outsource all of these items to paper, planners, and assistants so they can help you focus on the important and not only the urgent.
Start being a factory — where great ideas and plans come in, are addressed and executed, and are shipped out to your clients.