A preliminary discussion of the cultures of greater Hyrule

Before the Unification War (the war in which OoT Link's father fought) the peoples of Hyrule were all separate factions. The Gorons and Zoras were not kind to each other, nor to the Hylians. But the King of Hyrule in that time fought to bring all the peoples under one ruler (himself) and to promote cooperation and understanding between the races. That being the case, at the time we see in OoT there is still much separation, and the peace seems very tentative. Only a representative of the Royal Family of Hyrule is accepted as a Hylian into Zora's Domain, or onto Death Mountain.

Hylians

The people of Hyrule are mostly Hylians. They have long pointy ears (to hear the voices of the goddesses) and are predisposed to magic. Link is a Hylian, and so is Zelda, and so are most of the people Link meets in the games, at least the ones set in Hyrule. The pointy ears is a dead giveaway, assuming they don't better fit the characteristics of another race. Most people living in Castle Town are Hylians, as are most who live in Kakariko village. They appear to have most normal hair colors and eye colors, with no tendency for any in particular. It is theorized that the Hylians who have brighter red hair are a result of intermingling with the Gerudo.

Sheikah

The shadow folk, and the protectors of the Royal Family of Hyrule, Sheikah are a very small numbered culture who always seem to be just scraping by with one or two remaining obvious instances. However, at any point there are a larger number of Sheikah who are doing normal things, in odd places, who presumably continue to pass on the bloodline and keep the traditions somewhat alive. Sheikah were the original inhabitants of Kakariko village, and seem to have played some significant role in the Unification War, because many of them appear to have died shortly before Ocarina of Time, such that many people believe them to be extinct. Impa, however, is a confirmed Sheikah, and presumed to be a fairly high ranking individual, in whatever social hierarchy the Sheikah may have, since she is the closest to the Royal Family, as the personal guardian of Princess Zelda. Impa seems to be the most authority holding citizen of Kakariko Village, as after the Unification War, she opened up the village to poor Hylians, presumable because of heavy losses to the population during the war. Notable Sheikah include Impa, Impaz, and possibly others such as Dampe or Madame Fanadi. The dead giveaway characteristics are red eyes, as well as the Sheikah symbol (a single eye, usually shedding a tear, such as the one on the Gossip Stones) on them.

Gorons

These creatures eat rocks, and live up in Death Mountain where they can find them. They especially like the rock sirloin from Dodongo's Cavern, so much that foreign Goron settlements (i.e. the one at Snowhead) have it imported! It's easy to tell Gorons apart from other species, as they are extremely homogeneous as a race. They all have the same yellow-brown skin, which is so hard that they can walk on lava and roll into a ball and tumble down mountains. Some have spikes. They have blue eyes, and many carry the Goron symbol (something like a pawprint) as what appears to be a tatoo. Many seem to be in the mining business, which is how they get their food. Some take a liking to merchanting, however. Gorons cannot swim, but surprisingly they survived the great flood. Goron society is dominated by a patriarchal system with elders upon elders being given the right to rule. Gorons enjoy sumo wrestling, and hot springs, as well as just rolling around in circles. Gorons tend to be extremely isolated as a society, and do not take kindly to unannounced outsiders, not to say that they're racist, just careful. If a Hylian or Zora proves to be not a bother, the Gorons will be quite pleasant. Some Gorons, for reasons unknown, are much much larger than normal, these have trouble living among Gorons inside mountains, so they sometimes just camp on the outside. This might be a random birth defect or a certain family line that has happened over time.

Zoras

The Zoras are a race that seems to have grown closer to fish. They can stay underwater indefinitely, but seem to also be able to breathe out of water too. Thus, they are extremely adaptable. They appear to be led by a monarchy, and call Zora's Domain, the source of the Zora's River, their home. There are indeed two types of Zoras to be found in Hyrule, requiring different treatment. The River Zora or sometimes Zola are an aggressive race who will attack you from the water. They are less civilized than the Lake Zoras who live in Zora's Domain and at Lake Hylia, and should be treated as barbarians. This is not to say that River Zoras cannot be civil, but if they see no reason to be, they see all Hylians as enemies. Lake Zoras do not normally allow Hylians within Zora's Domain, but when they are encountered in a neutral area such as Lake Hylia they are friendly. It is thought that in the timeline stemming from the adventures of the Hero of Time in Ocarina of Time, including Wind Waker, the Zoras evolve into a different race known as the Rito, who can fly. It seems a little silly that the only strong swimming race had to adapt to the new water-based environment, but they did. The Zoras were hit hard in the other timeline by the freezing of Zora's Domain, but they ultimately survived as a race. There are some Zoras in Termina, but it is unclear whether they are in contact with the Hyrulian Lake Zoras, it seems likely that one stems from the other at some point in history, however.

Gerudo

The Gerudo are a desert people made up almost entirely of females. Only one male Gerudo is born in a hundred years, and he is to be their King. Ganondorf is the example of this position as Gerudo King. Though not an "evil" people in the sense of the River Zoras, the Gerudo make their livelihood by stealing. They call the Gerudo Fortress, in the Gerudo Desert, their hideout, and also seem to use the Desert Coloussus as their place of worship, probably of Din primarily, and maybe the other goddesses as well. The Arbiter's Grounds might be a place of the Gerudo as well, but possibly not. The Gerudo women are known to find mates among the Hylians (for lack of men of their own race) and they then take with them the children deemed to be Gerudo. The others are presumably left to the Hylian men to raise (Malon may or may not be an example of this phenominon.) The Gerudo are hostile to Hylians in a diplomatic sense, and do not submit to the rule of the King. Hylians are not normally allowed into the Gerudo Fortress, with entry only permitted to those with a membership card. However, it is thought that Telma, who lives in Castle Town is mostly or partially Gerudo, so some may be defectors, or possibly the Gerudo as a tribe have crumbled by the time of Twilight Princess, since Ganondorf has been unable to lead them from within the Twilight Realm. There is a band of pirates named the Gerudo in Termina, it is unknown if they are connected to the Gerudo in Hyrule, but likely. The Gerudo have yellow eyes, and dark skin with red hair, setting them apart from everyone else obviously.

This concludes our brief look at the peoples of Hyrule, with some groups left out. Wait for part II, I suppose, but these are the most important and historically relevant groups of people. Flat, signing off.