Respond with personalised comments rather than a generic Thank You. Fostering a conversation helps build the credibility of your blog!
Don't just type, talk to your audience. Blogging is way big a market on internet and people will like you if you do more than just providing information. Suggest, express, appreciate, criticize and have an opinion to build a relativity to a like minded audience. Make them feel that their visit to your blog matters to you.
Choose a template that suits your blog content. It not only adds to the blog's beauty but will also accentuate the content well. Bad design is always a put-off to readers.