If you're booking through a third-party site, check the hotel's site, too, which should offer details about the rooms, sometimes down to the hair-dryer wattage.

If a chain's site offers free membership to a program such as Starwood's Preferred Guest or Hilton's HHonors, sign up. Your new affiliation may get you a better room or a third night free. Even if it doesn't, you'll be notified about deals in the future.

Whether you reserve on- or off-line, find out if discounts are available for AAA or AARP members or government employees.

--Make sure your bargain is the best bargain. For instance, your AAA membership may get you a price lower than the rack rate, but the hotel may have an even better deal available for the same room. --Like airlines, some hotels now offer 21-day advance deals--and like airlines, they'll nail you for canceling. Third-party sites may charge a cancellation fee on top of the hotel's. Book only if you're certain about your dates.