Efficient driving

As a middle aged person(!) when I learned to drive many years ago, I was taught never to let the engine labour... my present tow car is the first one I have had which can give a running mpg figure as you drive, and I quickly discovered that the sooner you change up into a higher gear, the better the mpg figure- so I try to drive in 5th gear whenever it is feasible to do so. Keeping the speed down, and avoiding harsh acceleration is important, too.