You'd need to find a way to bring the United States into the war very early, because without them, and with Austria-Hungary neutral, there's just no way to bleed the Russo-German alliance dry. The only large land front for Germany is France, and the Franco-British alliance barely managed to hold on while Germany was busy fighting Russia and supporting AH; without that distraction, it's not going to end well for the French.
Positing an "Everybody else in Europe, plus Japan, gangs up on the Russo-Germans" then we have Britain, France, Italy, Ottomans, and Japanese, plus assorted lesser powers, to deal with. The French are already fully committed to staving off a German invasion, or else attempting to launch one of their own, the Italians have no direct borders so are going to be supporting the French (it's unlikely they'll be willing to directly assist the Ottomans, due to historical rivalries), which does leave Britain able to open up more secondary fronts - but where?
Russia faces no immediate peril in this setup. The Ottoman front is far from their center, as are the Japanese and assorted English colonies, so the Russian war machine isn't going to be crippled by huge land losses like they were IOTL. This leaves a stronger Russia battling across more limited borders.
Bringing the United States into the war is difficult, because a British blockade isn't threatening to starve Germany - they can buy all the food they need from Russia - so there's no reason for unrestricted submarine warfare. We need a secondary POD to tie the United States into a defensive alliance with another nation, presumably Britain.