Randy Petersen is the master of frequent-flier miles. As the editor of Inside- Flyer and WebFlyer.com, he'd better be. I asked Randy about reward travel, and he said he has one cardinal rule: If you don't find what you want online, talk to a live person.

You may have to pay a fee to talk to an airline reservation agent, but it's worth it: Your odds of getting what you want greatly increase. That's because airline reservation agents can access inventory from partner airlines. This is something that you can't do online. They can also easily try different routings, using connecting flights or alternative airports.

Booking in advance is helpful too, but even if you don't need to have your travel plans figured out a year ahead, you can still take advantage of the way the system works. Most airlines make seats available 330 days in advance, but frequent-flier inventory isn't always loaded into reservation systems that early.

According to Petersen, the sweet spot for finding open seats to go with those miles is three to six months ahead of your trip, which is a lot more realistic than planning a year ahead anyway.