I think a review of the basics would be a good start.
Once you have that down then start looking for aero mods that will improve your fuel mileage over the long term. This is the best piece I seen on fuel economy for over the road trucking.
cummins_secrets_of_better_fuel_economy.pdf
There are a number of good videos over on Youtube on the subject of better fuel economy in large trucks. The biggest gains can be made with driver improvement.
An example of this can be seen in this short video from Volvo Trucks.