Given the massive material superiority of the Entente the POD(s) for a non-phyrric CP victory have to happen prior to the war or in the early war.
The factor that decides the war in my oppinion is the interplay between British mobilization and French exhaustion. There was a window of opportunity for the Germans to decisively cripple the French war effort, before the British Army arrived in force. This window (without delaying British mobilization) is between 1914 and early 1916.
"Eastern Road to Victory"
"Conventional wisdom" in our community is that the right decision for the Reich would have been a stronger focus on Russia (2-3 armies instead of 1). In my oppinion this is tricky. Every scenario where Russia succumbs to Revolution is very tricky for two main reasons:
1) The Revolution was mainly the result of a political and economic crisis. I certainly don't want to hide the influence of the catastrophic casualties but I see the political and economic drivers as the main influences.
The political and economic factors certainly were interwoven with CP military successes but the "perfect storm" needed time to brew. Even more successful CPs would have been hard pressed to cause a Revolution prior to mid/late 1916 (in my humble oppinion). As the Germans learned IOTL, a Revolution does not equal victory. There might be another Revolution and Trotsky as chief negotiator...
So Germany, despite the likely French relief offensives, is going to face a much stronger Entente in the West once Russia is finished. The war at best is going to be a drawn out affair and we are dangerously close to "phyrric victory/loss" territory.
2) In the inevitable war with the now full strength Entente Germany is going to need Eastern ressources.
To bad that the Russian Empire is rapidly turning into a bloody mess. A light screen of occupation forces won't be enough if Germany really wants to extract ressources. So Germany will be tied down in a bloody mess they are ill equipped to deal with, while needing every available man in the West.
What the CPs really need, is an early compromise peace with a stable Russian Empire. The Empire should be able to shoulder the burden of supplying the CPs reliably with ressources.
"Western Road to Victory"
Here the path is fairly obvious from my PoV. A 1914 that destroys even more of the French warmaking ability and delays British mobilization more than IOTL.
Instead of Gorlice-Tarnow we see a Western Front offensive in 1915. This offensive lays the groundwork for the defeat. The French army doesn't break but has to endure horrible casualties against superior German artillery and tactics, probably bleeding themselves white in counteroffensives against a localized breakthrough.
France will be able to replace most of the manpower losses in 1916. The losses in the officer corps and the loss of a manpower reserve will be very problematic.
ITTLs French Army in 1916 probably is of much lower quality than OTLs French Army. If British mobilization has been sufficiently delayed, Germany can now finish off crippling France. When Britain arrives France will be the analogue to OTLs A-H after the Brussilov Offensive.
Germany now has the breathing room to favourably end the war.
I would like to know if you agree with my assesment. If enough people are interested in this discussion, I would like to discuss specific PODs.