Oh dear - a little off-topic…
To my mind, a major key to the game (and thus a good player) is unit count and IPC value. The player with the most land units at the end of the game wins. Units give you options, and the ability to limit your opponents’ options, the ability to control territory, and thus build more units.
Units at the front are more important than other units. Don’t lose these unless you are making the other side lose more of them.
So to my mind the keys are:Not letting your front-line units get killed without taking more down in return Get more units to the front more quickly Build more units - this means infantry Enable your units to exert their influence in the maximum number of places. This means Transports, tanks, and don’t lose your air units, maybe even build a few, but that will interfere with #3
#1 is tactics
#2 is logistics
#3 is economics
#4 is force multiplication, and allows you to do more of #1 and #2 with your existing units. You can evacuate, attack, create kill zones, shift fronts, etc.