I too usually book 280 - 300 days ahead. I make plans ahead of time and usually know where I want to go 2 years ahead of time. At about 360 days out I start looking at earlier dates and try to get a sense of where the trends lie. I book as soon as dates are available. No sense kicking yourself later when availability disappears.

Now a disclaimer. We usually book 3 people in business class. These tickets are sometimes harder to come by because of the number of seats we want.