I usually try to build up four main armies to attack Russia:
Far North: from Finland into Karelia, then south to Leningrad
North: from Poland into Baltic States, then some units to help take Leningrad
Center: from Slovakia/Hungary into East Poland, then usually split to take Belorussia and Western Ukraine
South: From Romania into Bessarabia, then on to the Ukraine.
Now, these groups will vary from game to game as to how much I will send to different battles. For example, sometimes the armor in Center Army will split off and join South Army to help take Ukraine. North Army may send more or less units to Leningrad, depending on Soviet defense there and availability of air cover. Also, my strategy may differ depending on Soviet counter attacks and whether or not they are successful. I try to build good sized armies in each group so I usually don’t attack Russia until turn 3 or 4.
Assuming everything goes good with my battles and any Russian counterattacks were not successful, here would be my territory conquests each round after Barbarossa has started:
Round 1 = Karelia, Baltic States, E. Poland, Bessarabia
Round 2 = Leningrad/Vyborg, Belorussia, W. Ukraine, Ukraine
Round 3 = Archangel, Smolensk, Bryansk, Rostov (Now Moscow is almost surrounded)
Round 4 = MOSCOW!!, Stalingrad, Caucasus and any other little territories I can manage to grab, perhaps by blitzing.
Of course, it doesn’t always work this way, but sometimes it does.