I have a few "rules" that I follow when booking flights:
Never check pricing on a weekend or holiday. I find the best time to price/buy tickets is either on Tuesday or Wednesday, that is when I tend to find the better deals.
Subscribe to all the frequent flyer programs and make sure you elect to have deals and flashes sent to you via email. If you get an email for a sale that works for you, act quickly - millions of others got that email to and those flash sales always sell out.
I start looking about 6-8 months out and almost always buy at or before the 90 day mark.
Know what's more important to you - flight times or cost - and be ready to sacrifice one for the other. For me, cost is usually king but there are some instances where convenient flight times are worth paying more for (like if you're traveling with very young children or live far from an airport).
Know your target airfare (say within a $50 range). I start out looking for my target airfare for a direct flight at the days/times I want most. If that isn't available I see if there is something at a less convenient day/time but still workable. If that's a bust I check for quick connections. If I still don't find anything in my target price range I call it a day and look again in a few days. I use Kayak to search unless I'm looking for SouthWest.
Know your max airfare. There is a tipping point at which a flight's costs make the overall trip costs unattractive and knowing what that is in advance allows for smarter decision making. If I see prices creeping up and getting close to my max and we've committed to the trip, I buy. We've also completely changed our trip to somewhere else when we couldn't get what we considered a decent airfare to our original destination.
Some other ways I've found to save on airfare:
We will sometimes fly in the night before, arriving at 10 or 11pm, and stay at an airport hotel then start our vacation already on the ground in the morning. This works especially well for FL for some reason and we almost always end up doing this when we go to WDW or Universal. Those late flights are usually the cheapest option and, depending on how many in your family, you can save quite a bit on multiple airfares vs. the relatively cheap cost of 1 hotel room for 1 night.
For WDW we will fly into TPA over MCO if TPA has a much better fare. Car rentals from TPA can be cheaper than MCO also and it's a pretty easy drive. This is probably a savings only if buying multiple airfares and renting a car already which we usually do.
If it's school vacation week for your home state or holiday/spring break travel - don't expect any bargains but do look at alternate airports. We once were going to drive 4 hours to NY to save $300 pp (there were 6 of us) and fly out of JFK because local schools here in Boston were off, and NY schools were not, so prices and flight times were so much better out of JFK (to San Juan)... When you subtract the gas and parking cost, we still would have saved over $1500. The trip itself got canceled for unrelated reasons before we booked anything but I still think this was a great alternative.
Hope some of this helps!
