Travelers can get better rates when they abide by certain rules.

Don’t book domestic airfares over the weekend, when prices can be considerably higher. In years past, sales lasted for a week or longer, but most of the sales we’ve seen this year have lasted only a few days. Eighty percent of the time, fares are launched on a Tuesday, and if the sale ends Friday, you will be out of luck when you go to book on Saturday or Sunday. You could end up paying double the fare.

Avoid peak-travel days. Fridays and Sundays are the most popular days to fly, and you’ll usually pay a premium to travel on those days. Fares for Fridays and Sundays can be 30 or 40 percent higher than travel on other days of the week.

The cheapest fares are usually Tuesdays, Wednesdays and Saturdays, so if you can be flexible, those are the days to book. As we approach fall, we probably will see deals on Mondays and Thursdays.

Compare per-person fares to multiple-ticket fares. If you’re traveling with friends or family and are booking online, check the price for one passenger and then compare that to the per-person price for everyone in your party.

For example, if you’re traveling with a family of four, check the price for just one seat, and then check the price for all four seats. If the airline has three cheap seats left and you try to book four, you’ll automatically be bumped up into the next fare class that has four seats available. So if there are three seats left at $200 each and the next fare with four seats available is $300 each, you’d be charged $300 each for all four tickets.

If you check the price for one ticket and there’s a per-person price difference when you try to book four, check the price for one ticket, then two, then three. If you can get three cheap seats, book those and then book the fourth, more expensive ticket separately. It’s much better to pay higher for one ticket than for all four.

Check alternate airports. Many travel sites, including Bestfares.com , allow you to check prices for airports near your first-choice destination. So if a nearby airport has a better price, you can see the savings.

This strategy can really pay off when you’re traveling with the family. We looked at late-August fares from Dallas to Baltimore and found round-trip fares were $334 to Baltimore-Washington and $271 to nearby Washington Reagan National. You could save $63 per ticket by flying into Reagan National; a family of four could save $252.

Compare hotel and package rates. If you plan to cash in frequent-flier miles and you’ll be paying for a hotel, be sure to compare the hotel price to bundled package rates.

When we looked at a stay at the Ritz-Carlton in San Juan, Puerto Rico, the price of the hotel for a week was $2,000; a package rate for two travelers that combined air and hotel was $1,600. If you cashed in your miles in this scenario, you’d pay $400 more than the package rate, and you would have wasted your frequent-flier miles. Save those miles for another trip, and use the extra $400 during your vacation.

(This article is by Tom Parsons on Dallas Morning News)