I don't want to trot out Craigslist, but at least I'm the first here to do it. Don't worry about visuals and instead focus on user experience. Focus more on making your application as intuitive as possible. Focus on adding just the right amount of friction to a workflow. Focus on creating discoverable features. Focus on the utility of the thing you're building.

There's no reason to worry about visuals--design happens well before that stage.

Now to give you an answer you can use right now.

Get your typography and whitespace right and the rest will follow.