This winter, the prices of gasoline seem to be going up even faster than the prices of crude oil. According to an NPR broadcast I listened to, this is due to the temporary loss of some refining capacity in Europe and North America. Gasoline prices may return to normal once production meets demand, but it'll never be cheap to drive around. This article seems to have some of the best tips for driving so as to save gasoline:
The ones that work boil down to:
1. Take it easy on the accelerator and easy on the brakes. This saves brakes, as well.
2. Drive the speed limit. Lower speeds improve gas mileage.
3. Use cruise control (except in the mountains).
4. Don't idle your car excessively. It only takes 30 seconds or so to warm up your engine significantly in the cold months (unless you live in Wisconsin or some other arctic region), and apparently this is one of the biggest gas wasters that the researchers found.
Of course, it goes without saying that saving gas also decreases your carbon footprint...