for optimal driving and petrol consumption:

if you are driving a manual then change gears at 3000-3500 rpm for optimal petrol consumption

if you drive an automatic vehicle then just firmly press the accelerator pedal and the car will auto shift on optimal rpm..avoid kick-down

for optimal performance:

if you are driving a manual then change gears just next to the red line..you can install a shift indicator which will alert you when you are reaching the red line so you can do the perfect shift and get maximum out of every gear (evil smile)..

if you drive an automatic then kick-down to get the maximum out of every gear..use sports mode/triptronic/steptronic/etc if available to get close to manual performance