Write regularly, neither too often nor too rarely. Two to three blogs a week is a good frequency to maintain.
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.
Put advertisement but make sure that your blog visitor doesn't get irritated when ads pop up one after another like a flood.