I stalk the airline websites, literally. I watch them and see the trend (so to speak) are the going up, going down, on what days etc. We keep hearing that it will cost more to fly anywhere this year compared to the last so when I see numbers I like then I will book and our WDW trip is in December. Right now, it is looking to cost us about $200 more for the four of us flying from Detroit to MCO. We are in London Ontario. That is not bad, but I have time to wait and watch a bit longer.
I watched a special that said Saturday's are the best day to fly, and Tuesdays and Wednesdays are when the flight deals come out. I will see if I can post the link on here.
A long time ago I signed up with Southwest, Delta, Air Canada, Jet Blue and so on to get their fare specials via email and they almost always come on a Tuesday.