Funding a colony is the most difficult challenge. The required technology can be mastered without too much difficulty. Mars One is trying the "bootstrapping" method by selling promotional items, but appears stuck at about $1 Million in funds raised. The Mars Society has done a lot of great work through annual conventions and in two research facilities. See last year's convention talk on funding a colony: The speaker recommends raising bonds. The Martian book and movie was very well done, but doesn't appear to have triggered many people to open their wallets to increase funding towards Mars projects.