Humans in the Star Wars universe were the most numerous and dominant species, with apparently millions of major and minor colonies galaxywide. They could be found anywhere, engaged in many different pursuits: mercenaries, pilots, smugglers, merchants, stormtroopers, assassins, farmers, crime lords, laborers and many others.
Humans
Humans were one of the first species to develop the hyperdrive, with Corellians being the first to do so. By this time, humans were already present on a few scattered worlds throughout the galaxy, which implies that they had a slower means of interstellar transport for a while earlier.
Nobody quite knows where humanity originated from, or how they came to be spread across a million worlds. Their homeworld is unknown, obscured by the foggy depths of time. Many have speculated that the species may have originated on Coruscant, hence the planet's dominance in galactic trade and as the governmental seat of power, both under the Galactic Republic and the Galactic Empire.
Humans always played a prominent role in the development of the galaxy and in galactic politics.
Most humans lived on predominantly human worlds, although many populations lived alongside aliens on other worlds, or together with several other species - something which was most common either in the cosmopolitian Core Worlds, or on the frontier at the Outer Rim of the galaxy, such as on Tatooine.
Human worlds included Corellia and Naboo.
Some famous Humans were Anakin and Luke Skywalker, Padmé Amidala, Leia Organa Solo, Boba Fett, Han Solo, and Lando Calrissian.
Near-humans
Several species in the galaxy appeared to be very closely related to humans, as they shared many physical traits. These are described as being 'Near Human' and are said to have descended from humans that evolved along distinct lines on other worlds.
Chiss
The Chiss, a race that dwelled in the Unknown Regions, were a humanoid people that had pale blue skin, black hair, and red reflective or fluorescent eyes. Their growth cycle differed from humans, with an early maturation and longer lifespan. In all other aspects they were normal humans: they bled red blood, and the cloning tanks used to clone human stormtroopers also worked on Chiss physiology.
Grand Admiral Thrawn was the most famous Chiss.
Hapans
Hapans were a near-human race from the Hapes Cluster, an isolated region surrounded by the Transitory Mists barrier. They were exceptionally beautiful, owing to a positive "bottleneck" effect: the region was colonized by pirates who had abducted a number of especially beautiful individuals from across the galaxy. Owing to the brightness (and perpetual day) of their densely-packed star cluster, they had difficulty seeing in dim conditions, and lacked human nightvision.
Tenel Ka, a Hapan, was also a Jedi in the days of the New Republic.
Sith
The Sith 'race' were an interesting case, in that their ancestry includes a non-human alien group that were genetically tampered with by a group of human Dark Jedi that settled on their homeworld, to escape from the Republic. The intermixing of human and Sith bloodlines, through the use of what became known as Sith Alchemy, created the Sith, with their characteristic red skin and long tentacle 'beards'. Due to their history of association with Dark Side Force users, the word 'Sith' went on to be used by many dark side organizations not connected with the original Sith species.
Zeltrons
Zeltrons are near-humans and bear a similar appearance, save for their pink skins, which may or may not be a result of their sun's highly radioactive rays. They are a highly sexual race, and are famous for their many sculptures and paintings on the subject. They also have made great strides in the field of holograms and are responsible for the ones used at Hologram Fun World.
Others
Other near-human races include the Theelin, the Arkanians, the Chev, the Omwati, and the Ubese. All these are mostly human in appearance, but have a few distinct defining characteristics.
The Duros were another species known to have a genetically distinct separate sub-species that arose from natural evolution, the Neimoidians. The Xexto and Quermians were also related, thanks to Arkanian genetic manipulation of the former to create the latter.