Paul Graham explains on how people who make things must manage their time to maximize their productivity:
When you’re operating on the maker’s schedule, meetings are a disaster. A single meeting can blow a whole afternoon, by breaking it into two pieces each too small to do anything hard in. Plus you have to remember to go to the meeting. That’s no problem for someone on the manager’s schedule. There’s always something coming on the next hour; the only question is what. But when someone on the maker’s schedule has a meeting, they have to think about it.
I think that the biggest sap on my own productivity is my failure to schedule my time to maximize it. I pride myself on being accessible and unperturbed by interruptions, but at the same time I think that keeps me from entering the mental state to really get things done.