I think if you have a fair amount of annual vacation, it helps to have some annual traditions for how some of it is used. Some of it may be around Holidays (Thanksgiving/Christmas), but even in other times I find it helpful to have other things I do every year, whether with a group of friends or as a couple.
I have gone between 3 and 4 weeks vacation in my last few jobs, and in a given year usually a week or two of that will already be committed ... annual golf trip, days around christmas, a weekday golf tournament we play every year, an extension of labor day to go up to a relative's cottage, etc
These are things I know I'm going to do far in advance, so it is easy to book them a long way out, and then the work schedule evolves around them instead of trying to fit days into a busy work schedule.
From there, its not that hard to eat up the rest with days here and there. I also like planning trips I'd like to take way in advance. The planning becomes part of the fun of the trip, and again you get it in your schedule before work gets in your schedule.