You have a created blog but have no idea about topics that you should write about. John has a useful tip just for you - Write what people search:
Most blogs aren’t read like a magazine, or like you might view it, they are found. In other words post the answers to the questions, problems, and challenges that you know your market is asking and seeking and your blog content will become the single greatest online lead generation tool in your mix. Discover the exact phrases people in your market are using when they search and write valuable content around that and people will find your blog before they know your competitors exist.