@ipoulin My one piece of advice for playing World at War has to do with the fact that some special units (e.g. US Mech. Infantry, German Panzers) are only allowed to be had in limited numbers.
I would figure out how many of what and then set aside a reserve of pieces just for those roles. I would then mark those units in a distinctive way: many people use paint or a marker pen to add a bit of color, you could also set aside appropriate WaW pieces just for those roles.
If you do that, you won’t have “too many” of a certain unit and it’s easier to tell them apart from regular units.
Once, when I was playing a game, a few turn in:
German player: “How many US Mech Inf have you bought?”
US Player “All of the infantry I’ve bought have been Mech Inf…”
Good luck telling that apart!
-Midnight_Reaper