Paul Graham has written an informative essay on his blog titled "Maker's Schedule, Manager's Schedule" that had Twitter abuzz this morning. Definitely worth the read.
I echo his statements on how meetings can be devastating for a makers schedule. They can just take the wind out of your sales, or worse, make it hard to even get started.
Lately here at the office we've been trying to use our calendar's (Outlook, Entourage) to mark off large chunks of time for doing work for specific clients or projects that we know we've got a lot to do. It sends a message to you and others that this time is reserved already, and I'm going to be productive and get things done. So far, it's worked out pretty well.