Watch for short service intervals.
Choosing a car with short service intervals means lots of expensive visits to the garage. Save money by checking before you buy - older diesels often demand lots of care, with some Mitsubishis called back every 4500 miles or six months. New diesels are on par with petrol engines at a maximum of 18,000 miles/two years, but some particulate filters need more attention. Renault diesels with the FAP filter for example need servicing every 9000 miles.
Pump the tyres up
Tricky we know with the UK forecourt network now shrunk to 1912 levels, but pumping the tyres to the manufacturer's recommended limit (and slightly beyond if you're feeling brave) does reduce your fuel bills. The harder the tyre, the less energy is needed to overcome the friction. Too hard, however, and you lose grip. Some tyres, eg. Michelin Energy, are engineered to have a low rolling-resistance specifically to save fuel and create a longer lasting tyre. Two things that might overcome their extra cost.
