the things mentioned don't cost anything and most are tried and true methods to increase milage.
Slightly overfilling (or at least correctly filling) tires saves treadwear and logically reduces drag.
I recall the gas crisis of several decades ago and they recommended driving as if there were an egg under your foot on the gas petal. Makes a lot of sense to be light footed.
Coasting sounds good but could be a trade off if not done carefully.
I also cut off my engine these days if I am going to be waiting more than just a few minutes. I'm not sure that will continue after the heat and humidity get here.
I can remember an old argument on cutting off the engine. Some say that starting the enging more frequently will use more fuel than idle speed but I tend to doubt it
I don't know about the Shell thing it might be the pumping variance you mentioned.
yeah but..