Humans: they're by far the more numerous and common of the humanoid races. From the barbarians of the steppes of Kara Kum to the kingdoms of men, they cover all possible human types and motivations.
Humans worship almost all divine powers. In fact, they are the only non-malign race in which you can find 'easily' followers of the dark deities.
In the Kingdoms of men, the most popular gods are Spenta Manyu and Ianna, besides the worship of specific clerical virtues.
The barbarian tribes don't have true clerics. Nevertheless, they have powerful and wise druids fulfilling that role.
Dwarves: they live usually in underground secret cities, only showing themselves up when they wish so. Only a handful of cities are on the surface and/or are known by other races. They're organized in clans, usually one by city and sometimes they trade with the nations of men. They were allied in the past with the humans to fight common enemies. They're pacific but good warriors. Though shorter than men they're built with powerful muscles and dense bones so they have the same mass scale than humans. They may live for centuries unless they find an unexpected, violent or fortuitous death.
They also have a +1 racial bonus to Strength and are able to see in complete darkness. They can carry very heavy loads for extended periods of time and are very resistant to disease.
Their religion is a mix of ancestors worship and faith on aspects of their traditional life. Some dwarves worship Xshathra on his blacksmith aspect, though they're just a few due to the whimsical nature of that god, not very appropriate for the estoic dwarves.
Elves: they live in the most ancient woods of the world. They're quite neutral, since the gods were banished from the world they haven't left the woods as a nation, only lone (or small parties of) elves are usually seen. In their woods they're quite strong, both by their natural gifts and also for their knowledge of the land. Only a huge army could fight them in that situation, for example. Something of their fine craftsmanship (also weapons) can be bought sometimes, like elven swords or bows.
Due to their distrust for other races and their little numbers outside their woods, half-elves are very rare; oddly enough, half-elves have automatically a good reputation (as if they were blessed) amongst humans, though amongst elves, they're much less well liked.
It's almost impossible to find an elf with less than 6 points spent on skills (instead of the normal 5)... that explains why they are one of the most powerful races in the world!
Elves had a more open attitude in the Age of Conflicts, when the gods still lived amongst mortals, before they were banished from the world by Ianna's spell. In that age, maybe by need, they still had many contacts with other races. But not too long after the gods left the world, when the need wasn't so great, they retreated to their lands.
They're very reserved and distrustful of the other races, perhaps due to the long time they've spent minding their own business.
They worship both Ianna and Spenta Manyu, both are important factors in the life of the woods. Besides them, there are powerful elven druids as worshipers of natural aspects.
Elves have Night Vision, are presumably immortal (except with respect to violent or fortuitous deaths) and immune to diseases, resistant to weather inclemencies and able to move both very silently and unhindered by natural obstacles like snow, mud, brambles, shrubs, etc.
Half-orcs: they're possible though very uncommon. Many of the more powerful orc chieftains are actually half-orcs, thanks to their superior advantages against sunlight, etc. In general, they're seen as full orcs by everyone, which makes impossible for them moving freely on civilized lands. Most of them (perhaps all) are evil.
They have a racial bonus of +1 to Strength and Health, and a penalty of -1 to Reasoning. They also have orcish appearance so they don't look too well except to orcs. They can run for extended periods of time and are able to see in complete darkness.