Ha ha... paying attention goes oh so much deeper than countdown timers...
What most people don't know is that you can improve your fuel economy rather dramatically using a variety of techniques commonly referred as "Hyper-miling". I didn't think much of it myself until I got a car that has a fuel economy computer built into the dash, and then it started to click.
See, brakes are death to fuel economy. Sounds obvious, but what isn't obvious is what that translates to in real world use.
Example: negotiating a red light. Most people don't pay attention to red lights until they are half a block or so away. If it's red, they start to apply the brake, and then as the light stubbornly refuses to turn green, they apply more and more brake until they stop behind the next car. Which is exactly the *wrong* way to get best fuel economy. Instead, you should be looking ahead as far as possible, and apply the brake as early as possible to reduce speed as early as possible to increase the amount of time it takes to cover the block distance while losing as little forward momentum as possible. Instead of waiting until the last minute and losing all forward momentum, you brake early and keep perhaps 30 MPH. This means that you don't have to accelerate to 30 MPH and you save that much fuel.
It was rather surprising to me how much difference I could accomplish using these techniques! On the freeway, if I drive around 50 MPH unless going up a hill, then more like 40-45, the normal 25-28ish MPG becomes closer to 34 MPG. Around the town, normally, my car (a 4-seat Chrysler convertible) gets around 18-20 MPG, but using these techniques about braking and reduced acceleration, I can get over 30 MPG on town surface streets! (flat land) Unfortunately, I do have to get used to being flipped off in order to achieve this.
In any event, you *can* get a rather sharp increase in fuel economy by paying attention to the forces of momentum, timing and friction.