With just the two of us, we are relatively flexible with where and when we travel. I do have some requirements, we tend to stick with 4 star resorts and like to travel in February. I check online sites daily, Redtag.ca and aircanadavacations.com are my go to sites. The last few years we've booked an Air Canada Vacations package. We have found some good deals with ACV and feel confident flying with Air Canada, so far we have had excellent experiences with them. Once I find a package at a price I am happy with, I contact our neighbour who also happens to be a TPI travel agent, Debbie Ford, allyourtravelneeds.ca. I like the security of having someone to rely on if things go wrong while travelling and generally TA's can match any deal you find online.
The key is to book a place you are happy with, at a price you are willing to pay. If you are not sure about a particular resort, tripadvisor.com has thousands of reviews on pretty well any resort around the world. The trick to reading and understanding reviews is to read multiple, look to see how the majority of reviewers have rated the resort and take those as the most likely reality. Keep in mind, what you are looking for in a vacation may be the opposite of what someone else is looking for, that's why all reviews, good and bad have some value. The forums are also great for asking questions of experienced travellers. I use it extensively, whether I'm booking a hotel in DT Halifax or and AI in the Caribbean. A little research can help with meeting expectations and avoiding disappointment.
From the East Coast Canada you are going to get your better deals just about anytime other than the first three weeks of March, schools in NS, NB and PEI all have breaks in March. I tend to find good deals a couple weeks out but if you're not fussy about where you stay and flexible on when you can leave, you can find smokin' last minute deals two or three days before departure. Right now you can get in to some 5 star resorts departing in the next few days from Halifax for under $1500 for two people taxes in. Warning, once you've booked at a price you are happy with, don't keep looking, that occasionally leads to buyer's remorse.
In my experience, if you can book an All Inclusive vacation at a good price, it's about the best value vacation you can get, anywhere.