The way I would start to colonize our solar system would be to first, build a fully functioning, public, space station orbiting around the Earth. This would provide as a starting point for the public who would want to colonize. The second step would be to build a smaller but also public space station around the Moon. Then you would start to Industrialize the moon. This is a big part in the colonization of our solar system and would need to be done. You would start by creating a big base on the moon along with many industrial plants. This would also be a great start to get people interested in moving to new planets without taking the long trip to Mars. The Moon would be a great producer in colonization ships because of its low gravity. With lower gravity you can produce larger objects and use a lot less fuel to get them off the planet. These ships could later be used to colonize other planets or even other solar systems.
I would now like to focus on the helpfulness of the Lunar Station. It will provide as a starting point for many missions as the gravity is lower and the Moon is a great slingshot for spaceships.
I will now let my opponent respond and talk about Mars and Venus in the second round.