I do a lot of design work, and the little details often consume a disproportionate amount of time. I'll have a sense of what the icon, photo or color should be and I won't stop searching and testing until I nail the zeitgeist of it.
More users of course. If you have an MVP, pile on the users, and give them a reason to share it with their friends. That way, you won't need marketing. Your users will do it for you.
You're going to have to "sexify" this site by about 1000 percent to make it work IMO. I suggest you get a copywriter to help you word it better (I can recommend one if you like). Also, amp up the color on the site.
The problem with Cheddar is that it's a todo app. There are a billion of them already. I wasted an entire afternoon trying to decide which productivity app to use (the irony was not lost on me). There's already too much choice.
FYI: I almost went with Nozbe but settled on Trello.