You must make your site as easy to use as possible. Potential customers won't waste their time trying to work out how to use your site. If it's not immediately obvious how they can get what they want, they won't do it. Not only should the UI (User Interface) be optimized, but the site itself should be designed to make it as easy as possible for visitors to convert to customers - i.e. it should be optimized for conversions.
You should always look to repurpose your content, because it is a great way to catch your customer’s eye. Get your most popular content, and turn it into an eBook or into a webinar, and you have a great way to not only attract clients, but retain interest as well. It is one of the most effective lead generation strategies that is around today. Wordstream has an amazing blog on how to do this.
The first three points in this startup checklist basically require you to do adequate research into your market. You have to know what the value of your offering is to the people you are offering it to. For example, there's no point in pricing your premium content at $3 a posting when the exact same content is being given away at a larger, more established site.