Jack Weatherford's “Genghis Khan and the Making of the Modern World” is a very much Mongol-sympathizing book, but makes some good points on the technologies adopted by the Mongols.

First of all — Genghis Khan did not live long enough to actually have to “manage” the empire. He mostly conquered it. The task of managing mostly fell on his descendants. Who promptly divided the empire into more manageable parts.

Still, the Mongols introduced some very important technologies, such as a postal system (stations with fresh horses; aspects af the institution's structure persisted in Russia, as an example, well into the XIX century). The records were to a much greater extent committed to writing, in part because of the much more regular tax system than what was usually present in the affected areas. Censuses were made (note the parallel w/ the Domesday book). Bureaucracy in general was a profession, and became more efficient as a result.

The maintenance of Pax Mongolica, the peace between the Mongol successor states, is also an interesting topic. Weatherford's narrative for this is that all possessions, while managed by various branches of the family, were still to some extent common property. So, e.g. the Ilkhanate had silk-making facilities in China, and their produce was dispatched to the Ilkhanate. So a constant flow of goods was a necessary part of familial relations. A constant flow of goods requires the existence of safe passages, so all branches of the family had incentive to maintain safe passage of merchants.

The problem was that Genghis Khan really couldn't. He spent most of his time conquering and expanding his empire, but never really administrated much. When he died, his successors never really could really administrate, so they'd either rely on their military power, or let local princes/government handle majority of it. The reason why the Mongol Empire never really lived much longer than 100 year was because it was a spread out empire, governing mass amounts of multi-ethnic multi-cultured people.

In short, they never really could manage the size of it, people were bound to rise up, so Khanates had adopt some sort of syncetic belief, maintaining their mongol culture, but accepting a religion or series of customs to show their populace that they were legitimate and were the right ruler for them. For example, the Ilkhanate mongols adopted Islam, since they governed a large Muslim population.