Bleh you wont learn much fighting the AI. I see two types of newbs online, hyper aggressive ones that fail in the first 5 minutes as they expand too much theyve usually learned from fighting the AI and the turtles, theyre in every strategy game they just freshly installed it and went online. Both are equally hopeless
Just play some "2v2 newb fun" games on maps like viers river valley and lyon, theyre easy maps with chokepoints you can learn the basics of the game there, queing up unit orders etc, whats good vs what. The game does have a lot of hard counters but theyre not absolute, a tank can drive behind an AT gun and mess it up etc. Also its a bit of a shame but the axis AT gun is miles better than the allied one as the axis one can cloak and it does more damage. This makes allied armor a bit rubbish.
Also watch the replay and see what the enemy did if you get whooped and dont understand why. I find its more fun doing that than watching random peoples replays or reading strategy guides.
Generally the best doctrines for each faction are:
Wehrmacht - Terror (for firestorm ability, V1 rocket, propagana, king tiger)
USA - Airborne (map dependant but mostly airborne for the paratroops and recoilless rifles and dropping AT guns from the sky and reinforcing the airborne from anywhere)
I dont know about the brits/panzer elite, it varies on different maps for them, those factions have been severly weakened through patches and are hopeless without being teamed up with a wehr or US. Brits can actually help out a US player but with the PE it would almost always be better if they were a wehrmacht instead, unless doing some crazy rush strategy.