Successful emperors throughout history have shared a few characteristics that make the job of being emperor much easier. The demands of ruling an empire are different than the demands of ruling a nation, and a good emperor understands that he needs to have the respect of his subjects.
An emperor is the sole ruler of his territory, and he must have control over all his people. This means that he must have the characteristics of a good leader. He must be confident in his own abilities and in the people around him. He must be a complex thinker, not too trusting and completely committed to the success of his empire. He must demand the respect of his staff and his subjects, and he must inspire in them the desire to please him and to hold the empire together.
An emperor is different than a king in that he rules not just one country but many territories. An emperor's subjects might not be naturally loyal to him or friendly to one another, but an emperor must be able to inspire unity among his people. He cannot have direct control over all of them because empires are too large, but he must extend his protection to his farthest-flung subjects.
Attention to Detail
An emperor must be able to understand all the elements that make an empire function. He must know how to keep an army, organize construction, choose laws and collect taxes. He must be able to keep track of all the major cities under his dominion and what each of them needs. He must understand the necessity of maintaining his roads in good condition and ensure that they are safe to travel. Most of all, he must be willing to delegate responsibility to people he trusts so that he does not have to personally oversee the day-to-day running of all of these details.
An emperor rules a vast area containing many groups of people. He must be able to see the big picture of how his empire fits together and its place in the world. He must look at events within his territory and around the world from the perspective of their effect on his empire, and he must be able to predict how foreign wars and politics will change his situation. Equally importantly, he must be willing to act on foreseen dangers and protect his empire from threats that have not yet developed.