Um it was a stalemate for most of its duration until the US entered the war so this is clearly redundant; unless you meant have the war end in a stalemate without major territorial changes, which seems doable.
If the Entente are able to regain the areas of France and Belgium lost in 1914 then I think that they could accept a status quo ante bellum type peace but they are never going to do that from a position of territorial weakness and unless very desperate I cannot see the CP agreeing either.
Maybe deeper reaching Haldane reforms allowing the British to stand up a trained Continental army earlier? And perhaps they focus on the Western front almost exclusively - ie manage to deal politically with the Ottomans / don't deploy a massive army to the Balkans