I like to play where there are mines in the danish sea that act as anti-aircraft for naval units. This really deters any major naval invasions of germany or shipping of troops to russia.
Also, to represent Germany’s superior armor, their tanks defend on a 3.
Finally, because the game starts in the spring of 41 and I like to think that one turn is a season, the United States cant enter play until turn 4 (cant do anything in the spring, summer, or fall), UNLESS germany attacks one of their shipping-box thing-ma-bobs or attacks any US units.