Hi Mazda3 - welcome.
Starting out, the best advice would be to record/track your fuel use, so you can watch your progress - that's your slo-mo feedback. The ScanGauge is an excellent idea - you won't go wrong there for the instant feedback you need to adjust your driving habits. (I should own stock in that company, I recommend it so often...)
You need to set up a
garage entry for your car in order to use the fuel log here.
I take it you've seen the
driving tips list?