Well the main key is more users of course. There is a rule about the value of a social media company that says if the amount of users grows by 10x the value does grow by 100x. Steem is still very small compared to big social media platforms. So there is a lot of space to grow.
Also it's important to have new Dapps like Musing.io , DTube , Steemmonsters ....
A other thing that will boost the price will me the launch of SMTs next year. In my opinion this does add a lot of value to Steem.