I have been playing A&A since it came out, and Germany has always been my best country. Although in both games (A&A and revised) the axis have the odds stacked against them, I find victories with them are more rewarding because they are so much harder to come by. Be that as it may, this is what I have found playing Germany.
In short, hit the allies where they are not strong.
Although the first turn buy is important, I see it as being more of a “feeler”. I tend to wait and see where the allies commit themselves before I decide what my exact strategy is going to be. The exception being Russia on t1 (because they are the only ones b4 germany). If Russia does the standard thing on T1 and fully commits to the German front than you should hold off. If however they get “creative” and send more than usual amount of troops to fight the Japs, than you see the weakness and should exploit it with large attacks on Russia. However that rarely happens.
As usual with most people who have some proficiency playing Germany, I knock the hell out of England turn 1 because they are spread so thin. The damage you can inflict on England before they can consolidate is never the same as on turn 1. Use your Air Force and navy to its fullest to exploit this.
Now it is a waiting game to see how the US and UK plan to wage war. If the UK goes all after Navy in the Atlantic, hit Africa hard. Your 1 inf 1 tank a turn will force the British to put large amounts of troops in Africa. If they fully commit to Africa, slam them in the ocean removing the threat of a cross channel invasion. If they go to India, same is true. There are only so many places they can spend $ and be effective. If they try to “do it all” they only accomplish losing on all fronts.
Now the real trick is with the Americans. If all 3 powers go all out against you, you have much fewer options. Thankfully in revised the Atlantic is not a quick jump over to the English sea square. Africa can still be exploited however because the US starts out with next to no navy in the Atlantic. Many games I have seen (if not most) develop into the UK building up an atlantic navy to threaten western Eurupe, and/or feed the Russians troops, while the US goes full force into Africa taking away much needed IPC. If this is the case, you really need to rely heavily on the Japs to do thier job and do it well since they are virtualy uncontested. However, your job turns into a delaying action to the inevitable. Airforce is huge in being able to do this well. 1 fighter or bomber a turn is huge in deturing an over ambitious US. With the threat of a large air reprisal on thier fleet where they land, the US and UK will need to overbuy ships to protect thier transports. Idealy, you never have to attack the allied shipping because they have gone to such a gross extreme over buying ships to protect it would be suicide. You still have your air force, and they have a bunch of ships that will never see combat (unlike your airforce which will see a lot of combat reguardless). This buys you time. If it is apparent that the Americans are going to go whole hog into Eurupe I suggest a very speedy conquest of Africa before the US can land in any force. You may be spread thin, but you get the short term IPC and than make the US chase you. Do not put your forces on the coast, put them one square away and make the Americans chase you. Move back 1 square every turn to stop the quick blitzkrieg. All the while they can never truly take you out because they will not have infantry support. If they try to take you out with only tanks and airforce than you got your $'s worth out of the Africa corp because they will be losing tanks to your infantry when they attack.
Air force is the key to German victory. You must give the Russian front “its due” of men going into the meat grinder. But a plane a turn for Germany will ensure a constant threat to the allied forces on all fronts. If you feel lucky, long range aircraft DOUBLE (in my opinion) the threat your airforce presents, and if you can spare the IPC I suggest you get it.
In my opinion a winning German player does not truly come into the game with a concrete strategy. As the Germans you need to look at it not as what you are able to do, but as what the allies are not able to do.
Create a situation where the allies are trying to stop a damn from bursting. As they plug one hole, open up another one and leave the small crack they have filled for the one you are now trying to exploit. The allies can not cover every “crack”, and you need to use that to your advantage. Sooner or later they will run out of fingers to plug the dam. Above all, do not fight thier fight, meaning a heads up confrontation against an allied concentration is suicide. They will win every time, they can out build you. If they are funneling troops to Russia spend IPC to take Africa away. If they want Africa hit Russia hard. If they are going all out to kill you, make them over spend to protect thier navy while Japan gobbles up the rest of the world.
The key to victory is the German airforce, with it you are a threat on all fronts. Without it you are fighting thier fight, and when that happens you better hope the Japs have thier shiznit together because if they don’t there will be hell to pay.