building ICs as germany, imho, is waste of money. you need +2 turns from building, setting in and using the units there. meanwhile you can build upt o a third more units, fast units if needed, to achieve the same.
but back to topic: strategies…there are some, but this map is bigger than other versions of a&a, so there is more flexibility in moving, buying etc. this sais, i can give only hints, but no real strategy - this you have to make up with yourself. :)
as germany: do not invest heavily in navy etc. build mostly mechs and tanks the first three turns, an occassional sub. thats all. in turn four decide: offense or defence. if offence once more mech an tanks. if defence infantry, one or two artillery, fighters. keep buying this the subsequent rounds.
as russia: standard buy with 28 ipc is 6 infantry, one artillery and one tank. if germany won´t buy fast units keep buing this. if it will then let the tanks go, build infantry instead.
see that you unit will never get seperated, seek for an option to unite them in one space, moscow finally. keep this option viable. anything else can be derived from this. even keeping or leaving valuable places as leningrad etc.
as britain: keep italy at bay first til the US can replace you there. remaining IPCs should be used for an unbeatable landing-force for france, step by step built, of course.
as italy: keep the med, keep egypt. don´t care about french northern africa etc. only destroy navies/forces you really safely can destroy. act massed if possible.
as USA: go italy first via gibraltar. help getting cairo back, saving an important victory city from axis´ control. get to rome during or after this. then go to france.
did this help?