My 2 cents...
I get better mpg by quickly getting up to speed vs slowly getting up to speed. My theory is that by slowly getting up speed the trans shifts sooner (too soon) and you lose the mechanical advantage of the lower gears to get the vehicle moving.
The brake pedal is the mpg killer. Using the brake kills the energy you have moving the vehicle forward and you have to use more fuel to get it moving again. Proper timing on your route to avoid hitting the brakes and coasting more will help a lot.
Cruise control sucks at getting the best mpg. The CC is a dutiful little guy, it will try hard to keep your very near the selected speed. It will slow you down and speed you up all very close to the set speed. If you manually control the vehicle you can let speed the vary to a larger degree. For example instead of using the CC to keep you at 65 +/- 1 mph, you can use downhill sections to gain a little speed and that will allow you coast for a distance. The same can be said for uphill, you ease you way up inclines while dropping a few mph when the CC would kick in and add throttle and the once over the crest the CC will slow the vehicle down again where you would be coasting.