As discussed in the Q & A thread.
Q: How do I get colonies on the map?
A: You must deliver some truly stellar and compelling worldbuilding and have substantiated your claim in an interesting cooperative fashion. Upon wishing to declare you have met these requirements ask Oz and he shall review your claim
For greater definition of what would meet these standards I refer you to the
worldbuilding guide and the spectacular story of
Other People written by one of our most prolific worldbuilders, Citizen-Diplomat Myroria. If you put effort into telling the bredth and depth of character driven stories others are likely to engage with such a story and thus support any claims made in said story.