metalstar316
Easiest one, from the start of the war might be to have either the Ottoman's stay neutral or defeated at Gallipoli and forced out of the conflict. This reduces the number of fronts the Russians have to fight on and boost's allied moral. More importantly probably the Russians can a lot more easily communicate with the western allies. Sending grain west, which reduces the allied dependence on the US and far more importantly still once the western powers get their act together they can equip the Russians better.
Even better one, but it requires a pre-war POD is that France sticks to its earlier, more defensive plans of meeting the German drive through Belgium head-on. French losses might be even higher but German losses would be a lot higher and France would lose less territory. This not only gives it more manpower and some of its most important industrial territory but also there's less incentive to attack to liberate lost lands - although this still applies to a degree for A-L. However it also means a stronger French position so it is calling less often for Russia to make desperate offensives to relieve the pressure on the western front. Germany is weakened by its appalling losses on the western front in the early months and is gradually forced to make peace.
Another option is a Germany goes east TL that goes pear-shaped for the central powers. They make early gains, although at heavy loses and drive the Russians from Russian Poland. However going for a total victory against a Russia with national identity consolidating against the invaders the Germans, say in 1915 advanced deep into Russia and overstretch themselves. [I.e. a 41 type scenario but with less railways disrupted by partisans/Cossacks and far less air and motorised forces]. German logistics collapse in the terrible winter and much of their armies are isolated with huge losses of men, material and moral. With Anglo-French forces pounding the weaker western front Germany crumbles and probably Austria-Hungary, which has shared in the eastern disaster, makes a separate peace. When in late 1917 Germany finally asks for terms Russia's crucial role in the defeat of the central powers is universally acknowledged.
Steve