If Russia pulls off stalemate in their East Prussia campaign in 1914 instead of horrific defeat we can have Russia in a better position. Just put a little pressure on Germany and avoid large numbers of men being captured, they probably can’t realistically win but don’t have to get embarrassed. Russia can slow down their military collapse and generally lose territory at a slower rate the next few years and they can thus drain the CPs a little more, which can cause a break through somewhere.
If France actually uses an effective defensive minded strategy in 1914 they can avoid losing as much land. They might even prevent Germany from capturing Belgium nitrates. More industry and manpower in Entente hands and less in German can enable the amount of pressure put on the CPs each year to increase and result in an earlier CP defeat.
If the Ottoman Empire stays neutral, the Allies are saved numerous fronts (Caucasus, Gallipoli, ME, Bulgaria) and Bulgaria stays neutral. Russia also gets greater access to global markets.
If Bulgaria is convinced to join the Entente, we can get the Ottoman Empire knocked out and Serbia secure, ensuring the above.
If Romania and Greece cut to the chase earlier due to timely deaths, they could join the Entente earlier. Bulgaria and the Ottoman Empires probably either join the Entente or stay neutral, and risk getting overrun if they join the CP.
If America joins the war much earlier. This could scare Bulgaria or even the Ottomans if early enough into neutrality. A tighter blockade is implemented and America manpower can ensure a win by 1917 if nothing else.