You cannot change the price of fuel, but you have more control over how much you burn than most people realise. The car matters, but how you drive it matters nearly as much.
Smooth wins
Hard acceleration and late braking pour fuel away. Reading the road ahead, easing off early and keeping a steady pace use far less, and on a motorway, sitting at a sensible speed rather than the limit makes a real difference because drag climbs steeply with speed. None of this means crawling; it means driving smoothly rather than in bursts.
Check the easy things
Under-inflated tyres increase rolling resistance and quietly cost you fuel and tyre life, so check the pressures monthly. Clear out the boot, since carrying weight you do not need costs energy to haul, and take off roof boxes and racks when they are not in use, because the drag they add is surprising.
Idling and short hops
An idling engine does zero miles to the gallon, so switch off in long waits. Short cold journeys are the least efficient miles a car does, as the engine never warms up, so combining errands into one trip, or walking the very short ones, saves more than it seems.
The honest limit
These habits trim a useful slice off a fuel bill, commonly into the low tens of per cent for a heavy-footed driver who reforms. They will not rival the saving from simply driving less, so where a journey can be shared, cycled or skipped, that is the biggest lever of all.