Diesel's usually get their best efficiency at their peak torque. Find that out and you have won half the battle. Sometimes you can find a BSFC map for your engine. That can give insight on how you want to accelerate.
If you have a turbo charger on a diesel install a boost gauge. Driving in a manner that keeps boost low shows you are driving efficiently (DO NOT MODIFY YOUR CAR TO LOWER BOOST).
__________________
|