1. Numbers of Users- by this if many user use bitcoin well it can encourage them because they can see it nice to use with the more user the more attention they will get.
2. Price stability- because of unstability of price some business afraid to adopt it because if price will drop they will lose big money.
3. History- history really tells and i think it will be helpful fpr business to look thw history of this coin by that it will also tell the future.
Well the main problem there is no marketing team. Bitcoin is for the people and the people should arrange everything. Which means do all the work. So far spreading the word seems to help, but the growth and impact seems minimal to me.