My best suggestion is just be yourself. Talk to people like you would talk to your friends. Post consistently and the readership will come. Good luck! Check out the Blogging Group to get more ideas and connect with other bloggers.
I recommend using an offline client and scheduling posts through that (plus, you can save your drafts). I personally (no, I'm not ready for launch) have set up an "editorial calendar" with themes for each day, as well as a couple of monthly features. I then took a physical calendar and filled in each day with that skeleton and am filling in each day with at least one PLANNED feature, so that I don't wind up as one of those very intermittent blogs that sometimes leave you wondering if the writer is still blogging at all. And, of course, anything that strikes my fancy can go in as I write it.