You found the flights you wanted at a decent price, but then you pull up the seat map to find only scattered middle seats in a non-reclining row next to the lavatory. Ugh.
Here are some tips to finding something better:
Pay up. This probably isn't what you want to hear, but the easiest way to get a better seat is to pay for it. I'm not talking about upgrading to first class (though that's great if you can) but doing something more affordable. Most airlines in the U.S. will let you pay a little more to get a better coach seat assignment. Some have seats with extra legroom that will cost a little more as well.
Go elite. Airline frequent flier programs treat loyal frequent fliers better. If you earn elite status (usually starting at 25,000 miles in a year on the big guys), you'll have better access to better seat assignments. The higher your status, the better the perks.
Follow the upgrade window. Let's say you don't want to pay and you don't fly enough to earn elite status. What else can you do? Look at when your airline starts upgrading elite frequent fliers. That can start as early as five days out. When that person gets upgraded, it opens up a seat in the back -- possibly an improvement on your middle seat -- that you might be able to snag.
Check in early. Airlines do hold back some seats that can only be obtained when you check in. So you should check in as soon as you can. For many airlines, that's at the 24-hour mark, but some may vary. (Air France, for example, is at 30 hours.)
Set an alert. This all sounds like a lot of work, right? Well, you can save yourself some time by setting an alert at ExpertFlyer.com. The service has seat alerts as part of its free offerings that let you find out when a better seat opens up on your flight.