Most hotel reward programs offer you two ways to get a free room: Either accumulate enough reward points or book enough nights in one sitting, and you get the room as a reward. But those aren't the only way to score a free room; booking package deals, booking a block of rooms at once, or being willing to let the staff "walk" you are all viable ways of getting a free night's stay.
Booking in Blocks
Any time you book a large block of rooms -- say for a business conference or a wedding party -- ask about the hotel's comp ratio. Ratios of 20:1 or 30:1 -- that is, one free room for every 20 or 30 booked -- are common.
Book a Package Deal
If you don't have your travel tickets yet, check out the travel-plus-lodging deals. Sometimes you can book tickets and a hotel room for only a couple of dollars more than you would have paid for the travel tickets alone; that's pretty much free.
Take a Walk
Hotel guests average about a 10 percent no-show rate, so hotels routinely overbook in an effort to keep every room full. If you get to the hotel and no room is available, you will be "walked" -- in other words, they will pay for you to stay at a comparable hotel in the area. Sometimes you can negotiate other types of reimbursement, including reward points equal to a free night's stay.