If you are near a major city, you are more likely to have a lot of options from different airlines, and thus the chance of getting a good fare. But you might be lucky from smaller cities, too.
Use Kayak or a similar search engine, and make practice searches of multiple airlines, for 2 months out from the current date, 4 months, 6 months and 8 months. The reason to do that is just to get an idea of price trends for different airlines and different times of the year.
Don't forget to search on the website of some of the airlines that don't list their fare on the generic search engines. In other words, Airlines that want you to look at their website for yourself. I think Southwest is one of those, but there might be others. Doing some practice searches from my area to Orlando, about 3 months from today, I get prices from about $280 to $360 from Kayak (I know these aren't great prices, and I'd keep looking) but Southwest at the same time, on the same days has a few flights from $180, and then a lot from $280 to $360. It just depends on what particular day of the week that you travel (often Tues/Wed and sometimes Thursday are cheaper) but it is worth checking out everything you can, because, as shown with Southwest, even from the same airline, prices can go in a range where the upper end is more than double the cost of the lower end, even on the same days. And prices will rise and fall, sometimes quite dramatically and sometimes over a period of only a few days.
If you are making a DVC Booking, then I would make it, and then keep checking on the airfare, until I found something I liked. DVC works best when you can book as far out as possible. If you are just booking a hotel room or resort, I'd still make the reservation and then look for the airfare, unless your dates are flexible, in which case you might search for the best airfare +/- a few days one way or another. If your vacation dates are fixed, by work or something, then you just make the reservation and keep checking for a good fare. You can usually cancel the hotel reservation or modify it without too much of a problem, but the opposite is true for airfare, which is difficult to change, and not cheap to change, once you have it purchased.