Preserving Germany's position by not having the World Wars is of course a distinct possibility.
Winning a World War One - equivalent is IMHO also possible if Britain stays neutral and Japan becomes a CP-ally. The enmity between Germany and France is a given due to Germany's possession of Alsace and Lorraine and France's wish to regain these territories. The enmity between Austria-Hungary and Russia is also more or less a given due the rule of Austrians and Hungarians over Slavic nations and the Czar's need for Panslavic propaganda.
I think the German-British rivalry is far less of a given. If it is to be avoided, then of course the POD must be early enough. The earliest and best POD is probably in 1884 when Bismarck acquired the first German colonies. It would be best for Germany not to acquire colonies at all, first for financial reasons - the colonies nearly all cost more money than could be gained from them - and second to avoid a rivalry with Great Britain.
Some more points where Germany could easily avoid a conflict with Britain:
- Not errecting tariff barriers against British goods (Britain did not retaliate with similar barriers in OTL and was still wealthier than Germany. Since this can help to reduce costs of living and production costs, this does not need to be a sacrifice at all.)
- Kaiser Wilhelm II refrains from sending the Kruger telegram or making the remarks that led to the Daily Telegraph affair.
- Germany does not start to build a fleet that is as big as in OTL. Perhaps the Haldane mission of 1912 is the latest possible POD in this respect.
- Perhaps most important, Germany does not violate Belgian neutrality in 1914. This probably demands a POD well before August 1914, where the political and the military leadership of the Reich coordinate their actions better and an alternative to the Schlieffen plan is developed.
It would probably not be necessary to avoid all the points of conflict mentioned. IIRC, Churchill has written that avoiding only the violation of Belgian neutrality would have prevented Britain from entering the war. Of course it would take a very different sort of leadership at the top to avoid enough conflict points.
If Germany had had no colonies, or at least no East Asian or Pacific colonies, Japan could have reaped no possible benefits from entering the war on the Entente's side. Given the fact that Germany and Japan are quite distant countries but had at the same time the same powerful neighbor - Russia - a Japanese alliance with the Central Powers seems to be possible.
A few PODs to make this possible that come to mind:
- Germany had not been one of the powers (along with Russia and France) that gave Japan the so-called "friendly advice" not to annex the Liaodong peninsula from China in 1895.
- Germany gives Japan financial support during the Russo-Japanese war.
- Germany does not supply the Russian Baltic squadron with coal on its way to East Asia.
The French navy is both smaller than the British and has bases that are less well-situated to blockade the Central Powers. Britain's massive financial power is not brought to bear to prevent neutral countries from trading with the CPs. A weaker Entente and stronger Central Powers might have made countries who were "sitting on a fence" such as Italy and Romania join the Central Powers instead of the Entente as in OTL. I have doubts whether the war would really be over as soon as 1915, but with the arraignment of powers just described, a CP victory seems more likely than the opposite result.
In the East, a partition of the Russian Empire, just as in OTL's Brest-Litovsk, seems to be the logical outcome of a CP victory. To make the various new states that arise on the territory of the former Russian Empire viable, it is probably best to give them genuine independence and have a customs union or free trade zone as the only formal tie to Germany and Austria-Hungary. The Polish nation is of course a big problem for the CPs even in the case of a CP victory. If a Polish state is resurrected only on formerly Russian territory, this state will have large Irredentas in territory that belongs still to Germany or A-H. Perhaps Germany can give Poland the Poznan province in addition to the formerly Russian areas and compensate for this in the West, e. g. by annexing the ore basin of Longwy-Briey and Luxembourg?? Serbia will be "punished" by giving the Kosovo area to Albania.
Despite a CP-victory the various nations in the Austrian-Hungarian Empire will continue to struggle for independence. Of course a peaceful dissolution of this Empire would be the best for everyone concerned. It is quite likely that the German-speaking parts of the former Austria-Hungary would want to join Germany, just as they did in OTL after World War One.