This is the approximate scenario behind my stories (it's a series, with more to come), occasionally referred to in the text, but also in the back of my mind as I write.

Date Event
2023 Robot Mining in NEA's An uncrewed mining colony is started in the Near Earth Asteroids, with government funding but built largely by big defense contractors. It brings everything it needs up from Earth, and plans to bring precious and expensive minerals back to Earth
2026 Crewed colony on the Moon The Chinese government, the only one still interested in manned space expeditions, succeeds in establishing a small colony on the moon, buried under the surface for radiation protection, and with regular runs to and from Earth orbit to replenish it.
2027 Robot Mining Fails A series of unexpected events and malfunctions leads to abandonment of the attempt to return minerals from the Near Earth Asteroids. Robots, being much dumber than science fiction would suggest, are unable to adapt.
2028 Humans Take Over A billionare resource tycoon based in Singapore but with assets in Australia buys the Near Earth Asteroid mining setup for a dollar, purchases heavy-lift rockets from Russia, puts together a team of practical engineers and geologists from the mining industry. These people take over the mine, with the emphasis now on bringing basic building materials to high Earth orbit. Ice, steel and plastics, in multi-tonne quantities are worthless on Earth, but in space they are invaluable. A person wanting to build a ship to reach Mars only needs to bring up light, high-tech components - the basic structure and the fuel comes from materials mined in the NEA's.
2029 Moon Base Secedes The people in the moon colony switch their attention from science to colonization, defying their masters on Earth. Using materials from the NEA's and engineering expertise from the company which mines them, they begin to build a near-self sufficient colony, which now welcomes colonists from all over the Earth
2030 Mines on Phobos Using materials brought back from the NEA's, a similar mining operation is established on Phobos, allowing ships travelling to and from Mars to refuel twice: once on arrival, for the downward trip to the surface, and again after lift-off, for the trip back to Earth. Now journeys to and from Mars need only provision for fuel and water on each leg of the journey, rather than carrying tonnes of material back and forth. Continuous manned colonies on both Phobos and Deimos begin this year, and permanent settlements on the surface of Mars are no longer isolated.
2035 Catapult on Moon Manufacturing on the Moon goes into high gear, turning out components and raw materials for habitats there and in the Lagrange points of Earth's orbit. Mag-lev railways are built on the surface for travel between colonies, and a very fast one is added, capable of reaching the Moon's escape velocity (about 7000 km/h). This is used to supply all sorts of materials to space colonies, and the standard 'cans' used for launching cargos become the standard habitat unit for stations and ships.
2040's Lagrange Colonies Exponential growth in stations and colonies in the NEA's and at the Lagrange points of the Earth-Moon orbit. Stations are not vast open spaces, but rings and binary structures built of habitat cans, so that single impacts by incoming meteors do not wipe out entire colonies. Miners and engineers completing a tour of duty in the Near-Earth Asteroids no longer return to Earth. Their skills and knowledge are highly valued in the new space colonies.
2045 Gordonmoore An asteroid which passes close to the Earth and then on out into the Belt attracts over two thousand colonists, bound for various asteroids in the Belt, with the intention of setting up permanent colonies there, or travelling onwards to other asteroids. This is the first major wave of colonists into the asteroid belt, but does not prove to be the typical settlement model.
later 2040's Colonies from Mars As permanent settlements are established on both Phobos and Deimos, these colonies mine their own raw materials and supplant the Moon as the main supplier of habitats and materials for settling the Belt. Transit asteroids pass close to Mars more often, and provide faster access to a wider range of asteroids in the Belt. Usually taking a year or two to reach their targets, colonies from the Martian moons are able to set out a couple of times a year, and the steady stream of people heading out to Mars from Earth are as likely to be destined for asteroids in the Belt as for the moons or the planet itself.

This may need some updating based on the more recent books and the remodelling work I've been doing in 2018. Watch this space.