But you are in charge of the Centrals, not the world. And if you do not attack (Centrals attacked first in WW1) then surly the Entente (allies) will.
Edit: I thought that because this is an Indian forum then maybe most members don't really know what strategies were really taken so we aren't going to get the same answers from everybody after considering what happened in reality, what proved affective and what did not.
For more background information:
1. As Germany you have a secrete alliance with the Ottoman empire so they would probably join the war with you pretty soon (they really hate Russia) and Austro-Hungery is there with you from the start. Sweden also really hates Russia, wants to capture Finland back but has an extremely small army so unlikely to want to join a war in a near future.
2. The Entente is right now only France, Serbia and Russia but Britain is looking for an excuse to join the war and Belgium is a highly likely candidate. Spain, Switzerland, Albania, Holland, Denmark and Norway are all expressing extreme neutrality and no will to join the war at this point or at any near future.
3. The Russian people are sick from years and years of oppression from the tzar (Russian king) and as the last painting tells you, Russia shows signs of a 4. revolution going underway (in reality, at first the Germans thought Russia would stay out of the war in fear of revolution but Russia turned out as one of the first countries to open hostilities that eventually led to war).
4. Western Germany is full of railroads that can help deploy units a lot faster but the east is the richer part of Germany.
5. In the place were Modern day Ukraine is supposed to be in, there are huge grain fields supplying all of Russia, something extremely important for Russia to hold tight.
6. As Germany, you have a huge navy, second only to Britain's.
7. Notice the lack of countries, that means there are a lot of suppressed nationalities ready to fight for their freedom (Largely most of Austro-Hungery, Poland, Finland, Ireland, the African colonies and the Arabs).
8. Greece hates Turkey. Bulgaria hates Serbia.
9. Italy had a triple alliance with Germany and Austro-hungery but now Italy surprises you and refuses to join the upcoming war with you.
10. There are subs, air ships (reconnaissance and bombing), early age reconnaissance planes, no fighter or bomber planes but there is cavalry. Lots and lots of cavalry for every army. There are no assault rifles or sub machine guns but there are machine guns and radio communications. As Germany, you also have a new form of weapon - gas (mustered gas) that you can shell you're enemies with by artillery. It blinds whoever is exposed to it and it can also kill.
11. Its August.
12. In the far east, Japan has an alliance with Britain. But they still really hate USA. USA doesn't want this war but they will probably help their democratic allies of Britain and France. China doesn't want a new big war with Japan so they are unlikely to want to participate in a war. USA is trying to protect China from Japan.
13. Latin America doesn't want a war, especially not with USA.
No need to bring up a book about how to run the war, all you need to do is give the general strategy with which you will want to start you're war with. Personally, I'm extremely interested in hearing what those of you that don't know how really happened will say.