It depends on what side you are playing. If your son is going to be Japan, tell him to follow the previous advice. If you are playing Japan, follow the USA-killing strategy in the Pointlessly Broken thread and effectively win the game in turn 5. Sadly something like 75% of the content in that thread is a needless flame war (as these boards are un-moderated for all practical purposes) but there is plenty of insightful commentary in there if you can suffer through it.
EDIT: I should point out that the war plans in that thread don’t translate that well into the Global game. If the USA can afford to ignore Europe for the first several turns of the game, then it has enough to place into the Pacific that Japan won’t take it down. Japan also has the issue of a possibility of expanding too quickly- since there are so many places it needs to reach, its forces will start to thin out all along the front. At that point the Allies can start to pick off Japanese forces piecemeal and slowly turn them around. I liken it to blowing up a balloon- if it gets too big, you can pop it. The Japanese are protected from this effect on the Pacific stand-alone map since they will run into the edges of the map which provides cover for their flanks.
