Ummm...so maybe this isn't the easiest thread/history challenge around, but it is this: make the Austrian army more successful against the Russians. Change of war plans, change of commanders (my wish: kill Conrad!!!
), etc. Make a plausible scenario wherein the Austrians can at the minimum stymie the Russian advance into Galicia (Lemberg); at the most, a second Tannenburg (as the title suggests). Oh, and destroy Serbia completely in 1914 (bonus if Bulgaria and Austria can do it quickly without needing German help).
Comments such as: "this is ASB, blah blah blah!" need not apply here
Comments such as: "this is ASB, blah blah blah!" need not apply here