Some sound advice from Gargantua and here is a bit more.
1. Get Abattlemap from this thread: http://www.axisandallies.org/forums/index.php?topic=12873.0
This will allow you to view games here and even play games here. I will give you a word of warning there are some very good players on this site, so do not be discourage if you decide to try your hand here and get trounced. You will learn from the experince.
2. This is a game I played with Darth Maximus. He is a good player here and was experimenting with something so the game does not quite progress as you have described but it illustrates several things such as the use of German bombers, building multiple ICs with Japan and a very aggressive opening with Japan as far as the options for J2. Since he was testing something there is a good deal of discussion between us and others watching the game. http://www.axisandallies.org/forums/index.php?topic=16748.0
3. I find not loosing the battle for the Pacific is pretty important in AA50. Note that I said not loosing, this does not mean you have to build ships and win control of the Pacific from the US, just that you do not want to loose. This also applies to the US. On this point is where I will give some different advice from Gargantua. If you know your opponent is going to fight in the Pacific by something cheap naval wise every round such as a destroyer. Japan starts with a lead in ships and it can be maintained. If the US starts spending all of its money in the Pacific by just enough units that your navy does not get outclassed. Japan wants to be focusing on taking out Russia. I like to have ICs in Manchuria, Kiangsu, French Indochina, and India. All of these will be producing ground units for Asia and depending on the game Africa with the Indian and French Indochina ICs. Sometimes I even build an IC in Burma. This frees up Japan's navy from having to protect transports for sending units to Asia and allows it and the transports that were sending units to the mainland from Japan to deal with the US in the Pacific, whether it is retaking captured islands or taking Islands to cancel the US Pacific NO.
4. Italy is a minor power and as such can really only do one thing well. Decide what this is and stick with it. Italy's choices are, contest Africa, defend France for Germany, or pressure Russia/open the door for German tank attacks. Decide which of these you want/need Italy to do and stick with that. Italy does not have the money or resources in most games to pursue more than one of these.
5. If you are used to Revised some things have changed. Bombers are now a quite good investment, especially for Germany. They can hit Russia, threaten Allied fleets and conduct bombing raids. This last I do not like risking German bombers on unless the UK's income is down in the 20s at that point I feel the risk of losing a German bomber is worth the economic damage to a weak UK. Also in Revised it was considered best to set up 4 transports servicing Japan before building ICs on the mainland. That is no longer the case. Japan can also afford to send transports to far flung places like Madagascar and just purchase more that will be where Japan needs them.
I see you mentioning defending Scandinavia, forget about it. The only concern with Scandinavia should be the fighter and bomber that landed in Norway on round one after sinking the UK battleship in seazone 2. Keep some German fighters and bombers in France for the threat to Allied navies and defense. Do not get behind on the buildup of units in France. France is easier to defend than retake. While this will allow Russia to make some initial counter strokes, that is OK since Japan should be building pressure on Russia.
Lastly I have an old thread that has my thoughts on G1 and they have not really changed so I will find it and bump it for you.