i got this from a friend. not that sure on the accuracy of all these tho, but they look quite reasonable and believeable too…
1- watch out your RPM meter, higher RPM means higher cycle, higher cycle need more combustion, more combustion need more fuel. yet too low RPM may cause your engine inefficient. theoritically at 3756 rev per minute petrol perform the most efficient combustion inside your engine. the best solution is to maintain your RPM in between 2500 RPM to 4000 RPM. ~ mmm… which one is the RPM? 
2- Try to avoid your RPM meter go above 4500 since its counted as acceleration and combustion inside your engine won’t have enuf time to burn completely. therefore it is declared as one good ay to waste your fuel if you don’t mind. ~ dis one patut can combine with the point above
3- maintain your speed. once you accelerated at suitable or safe speed, maintain it as long as possible since at this rate your fuel will be combust at constant rate or in easy word you save the fuel up this way ~really?
4- try to avoid braking too much. while braking your engine still running same as before your braking, therefore another waste of fuel, best solution is to also step on your clutch while braking, yet dont step your clutch when braking on the way down from hill, its dangerous. ~ siap ada warning lagi
5- keep your tyres at the manufacturer suggested pressure. this is to lessen the friction between the tyre and the road which will consume your horsepower and slowing your acceleration. thus slow acceleration take more of your time to achieve a desireable speed, more time to accelerate, more fuel will be wasted. ~ dingar tu!
6- fill your fuel at dawn, evening, or night. because filling the fuel under hot environment can easily evaporate some of your precious fuel. and also remember not to trigger the pump all the way up cause that may speed up the fuel flow in which the fuel might also evaporate due to formation of bubble as the flow of fuel hits your tanks. so make sure to push it half or slow. ~ hah? really???
7- consider of using manual car instead of automatic car. automatic car will only shift gear at a preset condition in which its hard to control your RPM in that way ~ ih, but if always jam, bagus lagi pakai automatic! sakit kaki bah mo tekan clutch balik2
8- much people say She** petrol can give you more kilometre, yet the side effect is your valve may get dirty (due to carbon-sulphur ratio) which in time will worn out and lead to fuel bleed, further cause incomplete combustion and pollution. thus your fuel will be wasted. try other fuel that offer protection of this such as Petron** or Calt** ~ nahh! kedapatan! the writer of this tips must be someone related to either Petron** or Calt**
9- keep track of your ‘TRIP’ meter, for instance every time you refuel set your trip meter to zero and start monitor how much distance you get for that much value of refuelling. calculate your daily basis distance travel and you can now made a budget of fuel expense base on that, this is to prevent you from excess kilometre that you dont need ~ ok, this one is good
10- whenever you are outing for entertainment or time commitment, try use public transportation as much as possible. its good for your health to walk around, you might find something on the way around, and most importantly its save your fuel!! ~ nah kaoooo!!!