With unleaded petrol prices reported to possibly be going up to 1.20 pounds a litre (that's 4.80 a gallon, i used to fill my tank for that when i began driving!), assuming you car is tuned, tyre pressures correct etc. post your fuel saving tips here - my suggestions i have tried and tested as follows...
1. Excess weight - leave tools, spare wheel and assorted boot junk at home except when going on a long journey, also only fill the tank halfway fortnightly instead of filling up once a month on payday.
2. Speed limits - stick religiously to speed limits, keeping well away from the car in front therefore avoiding harsh accelerating and braking, coast when possible.
3. Necessary journeys only - kids can walk to School, i had to, it will give them excercise away from their play stations, shopping can be done using Granny's shopping trolley.
4. Car sharing - ask that pretty blonde up the road who works at your place to take turns using each others cars - savings!
