2. Battery buster. Summer's heat, not winter's cold, is the leading cause of car battery failure. To minimize problems, clean corrosion from terminals, tighten cable connections and add distilled water, if necessary, to "unsealed" batteries. Get your battery tested if it's older than four years.
3. Choosing colors. Cars that are black, white or silver can fetch about $300 more in trade-in compared with similar models in red, blue, green or yellow. (Those three colors — black, white or silver — are also preferred by car thieves.)
4. Inflate and save. In warm weather, tires can lose air at a faster rate, reducing gas mileage by up to 4 percent. It's best to keep them inflated to the manufacturer's recommended pressure.
5. Don't trade too soon. The rule of thumb for trading in a car for a new model used to be 60,000 miles. But cars are better made today. Competition among manufacturers, anticorrosion protection and better lubricants are helping to keep many drivers behind the same wheel for 250,000 miles or more.
6. Cheapest to insure. Buy a minivan, pickup truck or SUV and you'll likely save on car insurance. All of the 20 least expensive vehicles to insure in 2012 are one of those types, according to Insure.com. Expensive sedans from Audi and Mercedes had the highest insurance costs.
7. Fuel saver. When you're running errands, drive to the farthest destination first so your car can warm up for maximum fuel efficiency. Starting with closer stops hurts your gas mileage.
8. Maximize gas rewards. Grocery chains like Safeway, Kroger and Winn-Dixie offer gasoline rewards programs. Get friends and family to share the card so points pile up faster.
9. Cost estimator. Repairpal.com gives free quotes for car repairs based on surveys of thousands of shops.
10. Complaint Dept. To learn what owners say about problems and repair costs for particular car models, go to carcomplaints.com.
11. Simply Sherlock. To confirm that your garage did tire rotations as promised, place a white mark on your rear tires; you should find it on front tires before you pay the bill.
12. B.Y.0.P. Some car repair shops will install parts brought in by customers, which could save you money.
Contributors to 99 Great Ways to Save 2012: Arthur Dalglish, Cathie Gandel, Joan Rattner Heilman, Sid Kirchheimer, Jason L. Lawrence, Marsha Mercer, Geoff Williams, Jeff Yeager and AARP members like you.