Because I don't like quitting, I shall continue my attempt to create the 10 Commandments of Blogging:
#1 Pick a Platform
#2 Win the Name Game
#3 Find your True Colors
#4 Hit Your Target
#5 Be Consistent
#6 Comment Unto Others
Commandment #7 is an important way to acquire 'regular' readers to your blog (not 'regular' as opposed to strange, but 'regular' as opposed to inconsistent). Blogging randomly is fine, but blogging thematically is fantastic. There are two key ways to turn random readers into regular readers through the use of themes.
1. Start a Series
Truth be told, this will alienate some readers who aren't interested in the topic. But don't worry about them, they'll come back. Others will be intrigued by your topic and will want to participate in a series of discussions. Starting a series is a method with as much potential as your choice of content. It gives your readers something to rely on when they visit your site. I tend to keep my series' between 3-7 days.
2. Dedicate a Day
Tell your readers that a certain day of the week (or month) is dedicated to a certain something. The possibilities are endless. I've even seen bloggers dedicate each day of the week to a specific kind of post, but I think that's going a bit overboard. The key is to find something that a good number of your casual readers are interested (if your dedicated day fails to get comments for a few weeks in a row, people aren't interested).
On this blog I tend to do 1 series each month, usually on a more serious issue. Each week, I tend to have 1 or 2 theme days. Currently my theme day is "Funny Friday's," but when the Fall TV schedule picks up I'll have, at least, "Office Quote" Thursday's.