I have been narrowing down resorts and asking TAs and photographers for quotes just to see how much I need to budget for certain times of the year. I want my budget to be realistic so I tell them my situation and they can generally give you an approx quote. If its just flights then I normally use Skyscanner or Kayak to check approx prices. You still have this year to research on prices. As 2015 approaches then you can see if the prices are good. I don't think there are too many options for direct flight from Vancouver down to Cancun area (if that's where you are heading). I think only Sunwing, Air Transat and WestJet fly direct.