You know, the best advice I can offer is to just do the legwork. Start stalking the websites of the airline or airlines that you'll likely book with and start learning what the pricing "cycles" are like for the route you want to fly. Pay attention to when new dates are released, what the usual fares are, when they come down in price and when they start going up in price. Pay particular attention to the times of the year you're interested in.
For example, right now I'm waiting for fares to come up for our Nov 2015 trip. Yes, Nov 2015. Our best airline choice for where we live in western Canada is United, connecting through Houston.
Right now dates are up for nearly all of August 2015. That means I can think about booking sometime in December, but I'll still keep an eye on what the fares are doing in the meantime. If the current trend continues the fares will come out at around $1200 per person for a round trip. Yup that's 1200 bucks!
After a week or 10 days the prices will mostly be at the lowest rate for our dates, around $500 per person or even less. That's a good price for 4000 miles of flying. They'll stay like that for a couple of weeks and then start to creep up slowly until they're right up to where they started. A week or two before, if any seats are left, fares will be at a lower price again, but not for all travel days or even all flights, so doing this is risky, to say the least.
Eventually you get a feel for your route and even remember other potential routes if you see them often enough. A friend told me she was going to New York. I responded, "Oh, that's the 7 am United flight to EWR." She just stared at me, thinking that I must be nuts to memorize airline schedules for fun. The truth is that flight was an option for connecting to MCO so I made a point of noticing it when I was stalking my preferred flights.
Obsessive, maybe. My wife probably thinks so, but she doesn't complain when we consistently get rock bottom fares when we fly.
