Switch and Octo touched on two points which I’d like to expand on, and they go hand in hand.
Switch spoke of the W Russia stack. W Russia commands 3 territories, all vital to Russian (and therefore German) interests in varying degrees- Karelia, Belorussia, and the Ukraine. A strong Russian force in W Russia forces Germany to choose a path and go in strength, or to sit back and trade units and territories. The W Russian stack also teams nicely with troops freshly placed in the Caucasus to enable a reasonable deterrent to Germany moving in force into the Ukraine. If the other Allies are properly doing their job, Karelia should be in the hands of a multinational force by the end of turn 4, preserving the 2 valuable IPCs for Russia without Russia having to do the work. That leaves the W Russia stack/ Caucasus combination to deal with Belorussia and the Ukraine.
Octo spoke of initiative. If you were to go back through all of my posts, you’d see that I’ve spoken on this topic many times. It’s IMO the single most important mindset to have in A&A. You must dictate the pace of the game, or at the very least attempt to appear as though you are. Take a look at the Russian/ German front. If Germany can get lodged into Karelia, they have access to Archangel, W Russia, Norway, and have pinned down 2 Russian IPCs. They can now in one move directly threaten the Russian capital. They can keep out the other Allies for a time. In short, they have gained the initiative in the north. The Germans are dictating the terms on the front. However, If Russia gets lodged into W Russia before Germany can get into Karelia in force, then Russia now has access, as noted above, to Karelia, Belo, and the Ukraine. Now Russia has the initiative, and Germany is forced to react to Russia, not the other way around.
It’s my humble opinion that forcing the other player to react to your moves (in this case the very definition of initiative) is one of the keys to consistently good play.