Personally, I'd just like to start with eliminating the monopoly the Democrats and Republicans have built for themselves within the election system.
These tasks completed, you could then make inroads, because those two issues are the chief reasons why third party efforts meet with limited success. Both parties regard legal challenges (so much for the will of the people, apparently), fine-tuning of election law, influencing of debate organizers and exorbitant spending on advertising to be appropriate measures for suppressing third-party challenges. Apparently, they have no interest in doing battle in the so-called marketplace of ideas, because then they might actually begin to lose some of their vast quantities of influence.
Once the two parties were thus forced to compete rather than strong-arm, third parties would become a legitimate alternative that could capture people's attention and excite their imagination.