When people ask me how to get promoted, I always have the same answer: start doing the job you want to get promoted into, and do it well, while still doing your own job. Eventually, the title will follow you.
For a lot of managers and CEOs, it's hard to think of a marketing coordinator they hired as a potential marketing manager, director, or VP. It's a big trap to watch out for, and an important habit to break. Every organization should aspire to promote employees to more senior positions as the company matures and grows. This is especially true of startups.
Whenever possible, groom and promote people from within your organization. It's good to keep talent within your company, and it's good for you to hire younger (and more easily molded) talent. And the possibility of a promotion is a great motivator. Hire all your senior staff from outside, and you'll be removing another incentive for more and better work.
While these considerations apply just as well to any company, big or small, there are other considerations that are more specific to startups.
When a major pharmaceutical company needs a new sales leader, they have an obvious and large pool of candidates to draw from: current or former sales leaders at other major pharmaceutical companies. What if a company that specializes in email deliverability needs a new consultant? Or a company specializing in 140-character updates needs a new SMS engineer? There aren't nearly as many ...