We fly out of PDX. We usually start looking online at kayak, orbitz, expedia about 6mos in advance and if we can get airfare under $300 a person including all fees then we're doing pretty good. Usually, we end up buying airfare at about 2-3mos prior to the trip for fear the rates will only be on an upward swing. We always buy directly from the airline site, whether it be Delta, Frontier, etc. Sometimes there are extra points given for ordering directly and we always sign up for the airlines freq flyer program. Currently we're using a Frontier CC to build points which we will use at some point to help defray airfare costs on a trip. Sorry no other "tricks" although I'd be interested to read what others like to do!
Whatever you do, once you make your purchase, stop looking! It'll only drive you nuts if you see a better fare.
hth