Avoiding weekends
As a rule, I try to think in terms of midweek travel (Tu, W, Th) because many people on vacations tend to travel in week segments (taking a full work week off), meaning that there is lots of competition for awards on Fridays and Sundays, which spills over to Saturdays and Mondays.
So, rather than competing with all that, I try to schedule vacations Th-Th or something like that, and have found awards to be more readily available as a rule.