The world as a whole will be designed with the intention of making it easy to run a Mythic Fantasy style game. This is not to say that other styles won't have their place; however, it does mean that the core assumptions will lend themselves to this style of game and that other styles will have to bend (or even break) these assumptions to fit.
Gods Walk Among Us. The gods are real, and they walk among their people. Although many of the gods seek to better the lot of mortals, an even greater number are petty anc cruel. They intervene in the affairs of mortals, for good or ill, ruling kingdoms, raising armies, and generally amusing themselves at the cost of those around them.
The World Is New. Their is no ancient history beyond that of the gods. The Elder Gods created the world, the Greater Gods carved it into their own images, and the people dwell in the freshly crafted remains. Few, if any, kingdoms have fallen. Ancient tombs simply do not exist. There is the legend of the gods creation, and there is now; very little lies in between.
Much of the World Is Unknown. Pockets of civilization abound, and the pathways between them are well tamed, but beyond the vale of society lie great swaths of untamed wilderness. Here, there be monsters and other untold horrors. Beyond the interests of the gods, only fools and the foolhardy dare to tread.
Individuals Shape History. No coalition of men, no army of thousands, no kingdom of warriors has dominated the scene. Powerful individuals step into the spotlight and perform heroic or heinous acts, inevitably leaving their mark upon the world. Even when armies take the field, it is their generals, wading in and slaughtering scores, that turns the tides of battle. The power of the individual starts with the gods and is disseminated among those below.
Monsters Are Uncommon. Terrifying beasts do indeed stalk the land. But, when such a beast is seen, word spreads like wildfire because of the rarity of such an event. To find a monster, one need usually seek it out. Any such creature, be it owlbear or dragon, that is found near to civilization is cause for great concern indeed.
Magic Is Rare. The gods have divine power, and they grant a portion of this power to their priests and acolytes, but the mastery of the arcane is a rare thing indeed. While some cultures make look upon a hedge mage in wonder, many will gaze with scorn, and the rest will take up arms against such unnatural talents.