NEW YORK - When the economy was booming, many hotel companies began building new properties. Some of those are opening now, resulting in a 2.5 percent increase in hotel room supply this year, just as demand is dropping by about 1 percent or more, according to Jan Freitag of Smith Travel Research.

“We’re going to see a substantial decline in occupancy this year,” agreed Bjorn Hanson, an associate professor of hospitality and tourism at New York University’s Tisch Center.

Excess supply means opportunities for consumers. Here are some strategies for booking hotels on a budget.

BASICS: It’s generally cheaper to stay in major cities on weekends, when there are fewer business travelers, and in resort areas on weekdays and offseason, when there are fewer tourists.

Visitors to urban centers may save by booking outside main tourist areas. For San Diego, for example, “you could stay in Carlsbad or even up as far as Oceanside,” said Joe McInerney, CEO of the American Hotel & Lodging Association. But research the cost and time of commuting in each day, to make sure the trade-off is worth it. McInerney pointed out that hotels on Long Island or Westchester, N.Y., might be cheaper than Manhattan, but your savings might be offset by daily train and cab fare or tolls and parking.

You’ll also pay less outside of peak holiday time, and some new hotels charge lower introductory rates. Canyon Ranch’s new destination spa in Miami Beach, Fla., has nightly prices starting at $200 through Dec. 3. Rates go up Dec. 4-23, starting at $650 a night, and Dec. 24-Jan. 1 to $1,100 a night.

Places hit hard by the downturn may also offer deals. The Bahamas’ Atlantis megaresort, with nearly 3,000 rooms on Paradise Island, recently laid off 800 workers. It’s now offering a three-night package starting at $299 a person, including two sessions interacting with dolphins (normally $110 each) and $99 airfare each way on JetBlue [JBLU] from New York, $89 from Boston (book by Dec. 18, offer ends Dec. 25, atlantis.com, blackouts apply). In addition, the Nassau Paradise Island Promotion Board is offering a $250 rebate on air-inclusive packages (three- to six-night stays, book through Nov. 30, for travel completed by Feb. 28). An Atlantis package offered this time last year started at lower rates of $259 a person, but did not include dolphins, airfare discounts or rebates.

REWARDS PROGRAMS: Most hotel chains have loyalty or frequent-guest programs that allow you to use points for free nights. “Every traveler should be a member of every frequent-guest program,” said Hanson. Joining usually costs nothing, points accumulate and often don’t expire, and most hotel chains now have no blackout dates for using points to book rooms.

Many hotel chains offer co-branded credit cards with enough bonus points for a free night. Sign up for a new Marriott Visa card and get a certificate for one free night’s stay, plus 25,000 bonus points, which are enough for another night’s stay at Marriotts in many markets, including January in Miami, where you can go to the beach, or Salt Lake City, where you can ski. If you travel with a spouse or friend, that person can sign up for his or her own card and get points for free nights as well.

Research how fast points accumulate before signing up. Different chains have different systems.

For overviews of what each hotel credit card offers and how many dollars you must spend to accumulate more points, check out creditcards.com/travel-rewards.php.

But be aware that when you apply for new credit cards, “it impacts your credit card rating,” said Gail Cunningham, spokeswoman for the National Foundation for Credit Counseling.

Avoid rewards credit cards, Cunningham says, if you carry balances from month to month. Don’t let the value of your rewards get wiped out by interest. Rewards credit cards, Cunningham adds, are only for those “with the most pristine of credit ratings.”

BOOKING: McInerney of AH&LA says your first stop should be the hotel’s own Web site. “That’s where you’re going to get the best price,” he said.

In addition, said Hanson, “most brands have a guarantee that if you find a lower rate, they’ll match it or pay the difference, or you can stay for free.”

Ask for discounts for AAA membership, military service or corporate rates.