Get the ScanGauge and use it to monitor and improve your driving.
If you want to do a grille block before you get a scangauge, you could wire up an LED to come on when the radiator fan does. Then just block as much as you can without having the fan come on often.
Check out this thread which has some pics of construction technique:
http://ecomodder.com/forum/showthrea...goal-8683.html
I would also add a block heater, and maybe while you're plugging the car in, add an alternator kill switch.