as allies, you need a logical plan, the standard allies play, focuses on pacific, middle east, africa and medit sea. The atlantic and saving russia is not in the equation, just protect uk, if you lose uk, usa rushes for it back, hopefully you spent the full uk income on london so that you inflict enough casualties on the germs so the russian bear can hibernate in romania without getting sick. This ain’t hard. Preferably solving the pacific puzzle before russia falls so uk/usa can just protect london and egypt and wam bam thank you ma’am axis lost next game. It’s a race and it is the typical strategy.
Other players like to do europe play and bring the minimum for the pacific, which is fine, you just don’t drop any men just keep building up a massive 1 shot force to take italy or liberate france or hit west germany/denmark then storm with uk on germany. You would still need italy shutdown from making income, which is not hard considering you can convoy them out of the game. This is how people race europe before usa has to go full pacific to stop the pacific win.
If you want to do a balanced plan, uk still focuses on the med, usa will bring the naval for the london fleet or supplements it with carriers for uk air and dds, brings the convoy subs etc.
Some axis plays require a direct counter strategy. Usually the “gambits” / rushes, in which case you do that.
In any case, allies need to figure out what they are doing and just do it. The allies have always focused on the big picture and global is very unforgiving for players who don’t see that.