How do I maximize MPG? from miles per hour

Drive like you had an egg between your foot and the gas pedal. Avoid fast starts, 60-63 MPH on Interstates, use cruise control, keep tires properly aired, engine properly maintained, including air filter, avoid city traffic when possible.

The best fuel mileage is driver controlled.

I agree with all above.

55mph +/- 5mph pending. Take advantage of a good tail wind by going 60mph. But a head wind try to maintain 55mph, but don't force a particular speed. Don't fight wind or inclines. Let the rig slow down some, but don't become a road hazzard either. I watch which way and how much tall grass far off the road is leaning. It's a good guage on wind speed and direction.

It helps to drive stocking footed to feel the pedal better to determine how far down you are pushing it.

Using cruise control is bad news for fuel economy because it will go full throttle up every over-pass, and then engine brake down the other side. I wished I could set the throttle to a window of variance to let the rig slow down some up hill and coast fast down hill.

There are some other tricks like taking off Cruise Control when going up a steep hill other wise the CC will try to maintain the 55 mph and pour the fuel into the engine to try to do that.
Don't try to be the first one off the starting blocks at traffic lights. Coast into stop lights, like the truckers do, so you don't have to come to a complete stop.
There must be others...

55MPH