Years ago I won a fuel-economy competition driving 150 easy miles or so along a major highway. And I beat a bunch of pros in the process.

Was I brilliant? Absolutely not. I was just slow and smooth, nothing more, but it was good enough for 9 mpg or some such number.

Mind you, I never did beat Caterpillar's longtime driver-trainer, the legendary Jim Booth. Came close on one long run we took together, but I just wasn't as gentle on the throttle as he can be. I wasn't willing to go as slowly, either!

I hardly need to say that there's mighty good money to be made by driving that way. Fact is, the worst driver will get as much as 35 percent less fuel mileage than the best one, which offers a ton of room for improvement. There's just nothing else you can do on the efficiency front that has such an upside. Nothing.

But it's a complex business, figuring out fuel economy, because the variables just never stop mounting up. Depending on where and what and how he drives, one guy might be deliriously happy to be on the right side of 5 mpg, while another would be considering suicide if he dropped below 9.

The only real marker here is the driver's own. So before you launch your drivers into a self-improvement program, first determine just where the individual's average fuel mileage sits - for a given run in a given season, making sure to compare apples to apples. Then you can start adjusting and you'll both see what works and what doesn't.

The following driver tips are compiled from many sources, mostly from the terrific booklets on fuel economy offered by Bridgestone, Cummins, Kenworth, Michelin, Volvo and others:

1. Slow down. If you get, say, 7 mpg at 55 mph, then it'll be 6 mpg at 65 mph. And at 70 mph, you'll be down to 5.5 mpg. Not small differences.

2. Spend as much time as you can - 90 percent or more - in top gear. Don't get in the habit of cruising one gear down.

3. Use cruise control if you're on flat terrain - and dry pavement. In hilly territory, the cruise control will probably try to accelerate too quickly trying to get back up to speed after cresting a grade.

4. Aim for the lowest number of engine rpm. With many engines, you'll win by cruising at about 1,300 rpm.

5. Use the engine's full operating range before downshifting. All modern engines are happy to pull at 1,000 rpm or so for brief periods. Stay at peak torque speeds or slightly lower when accelerating.

6. Try to maintain high - but legal! - average speeds. You can do that in several ways, starting with keeping a high field of vision and staying well back from the vehicle in front of you. That allows you to anticipate changes in traffic and road conditions and lets you avoid rapid deceleration or abrupt stops. You'll waste fuel getting back up to speed.

7. Try coasting to a stop gradually instead of staying on the loud pedal and then braking hard.

8. Get access to the information in your engine's black box and analyze the number of sudden decelerations and service-brake actuations you make. Use this info as a benchmark to improve against.

9. Old issue, but you really should minimize the amount of time your engine idles. Every idling hour can decrease fuel efficiency by 1 percent. Sometimes there's no choice, in which case choose the lowest idle speed possible, like 600 rpm or so.

10. In rolling terrain a light throttle is the way, and allow momentum to carry the truck over short grades. Again, turn off cruise control because your foot will be - or should be - much lighter on the throttle.

11. If it's quite hilly or mountainous, use the engine's full operating range before gearing down.

12. Plan your routes to maximize time on multi-lane highways.

In the end, the two keys are patience and more patience.

From the June 2011 issue of Heavy Duty Trucking magazine.