Wow, diplomacy can really have a big impact in this game. For the start of the campaign game, both AI markers were set just to the right of center (as was suggested in these forums as providing the best position for historical accuracy). I controlled Austria-Hungary while the AI played Germany. I can't remember where exactly I sent all my ambassadors for every turn, but at the start I kept sending zero level ones to Britain.
The game ended in early 1918 with the CP as the victors and Britain, along with the USA, never entered the war. Revolution took out Russia Mar-Apr 1916 with only Romania remaining in the east. I spent a few turns to better position my troops to pounce on her cities. Since all my forces were on this side of the map, decided to take care of Greece so tried to goad them into a war via diplomats. Instead they joined my side and Romania capitulated after taking her cities.
Now the long haul westwards, with eyes on Italy. Again, using diplomats, tried to get her to declare war on me. By Jan-Feb 1917, had enough troops to start an Italian campaign, but to my chagrin, no shots were fired and Italy joined the CP. The rest of the game was spent moving troops again to attack France through Italy.