Great advice given so far in here.
I'm a massive fan of thrifty driving.
I've had 52mpg out of my Arosa
and 37mpg out of my Alfa.
I'm not a genius in physics or anything so don't take what I say as golden but these are things I do/have done which I believe have/can all contribute/d to better economy.
Reduce friction every way possible-Get narrower tires with a harder compound keep them inflated near their max
-remove and blank off the passenger side door/wing mirror or even remove both mirrors and replace them with internally mounted mirrors
(2 rear view mirrors needed for MOT)
-If the underside of your car is relatively smooth slam it to the floor
and it will reduce the turbulence of the air beneath your car,
this in turn also reduces the gap in the open wheel arch which again reduces resistance (open wheel arches are really inefficient aerodynamically)
-Buy some moondisks they look cool and they'll improve the aero qualities of your car
-Clean and then Wax the curse word out of your car, a slippery car is an aerodynamic car
-Keep your trans and drive-train nice lubed up
-Check your tracking/camber/alignment tires scrubbing over the road surface is again going to cause pointless friction
Think logically about fuel usage.. when and where you buy it-don't drive miles to save less than 2p a litre, you'll spend that getting there and back!
instead be mindful of the price of fuel, when you see it priced well, go buy some.
-Got to be somewhere? leave earlier, leave in plenty of time, If you think logically driving 10mph slower but allowing yourself an extra 10 minutes on your commute (I commute on A roads sorry to everyone stuck in traffic) think of it logically going 10mph faster will only get you to your desk 3 maybe 4 minutes earlier (depending on how far you have to travel ofc) is it really worth it ? are you going to earn the £3.47 your journey cost you in 4 minutes ? proably not.
-When you arrive at your destination and are parking your car; you are getting 0miles to the gallon.
Park your car so that you can make a quick escape with minimal maneuvers. ie take the time to reverse into the space/driveway that way when you come to leave you can just drive straight off
Reason being: your engine will be most efficient when it is running at temperature.
So by maneuvering the car into a parking space at the end of a journey it is idling more efficiently than if you were to maneuver it with a cold engine at the start of the journey
- In an ideal world we wouldnt have the need to carry excess fuel (excess weight) .you could plan all your journeys like NASA and calculate just enough fuel to get you there and back, unfortunately the roads are an unpredictable place so this isn't really plausible.
Maintain momentum:-Need to turn left across the road? look, adjust your speed, calculate whether you need to stop if not why not just take the turn at 25-30mph?
do you really need to stop obviously be very sensible about these kind of maneuvers.
-Same as above applies to roundabouts, not a lot of use on busy ones but look, assess and look and decide if you actually need to stop or maybe you can take the roundabout at 30,40,50.. without using the accelorator
quite comical having tire squeel coming from a totally silent car.
-Leave a bigger gap between you and the traffic infront
-engine brake (fuel injected cars create a vacuum in the fuel pump when you do this so no fuel will be used at all I believe) I recommend feathering the brake pedal just enough to switch the rear bulbs on
as if a driver is close behind you they may not read your progressively slowing.
Thats enough for now..
Basically build something that looks like this:
as your daily driver
and
then drive it like its one of these:
I find driving like this really good calm fun, especially the maintaining momentum, you just glide about really smoothly