#1 Pick the Platform
#2 Win the Name Game
#3 Find Your True Colors
#4 Hit Your Target
The 5th Commandment of Blogging is "Thou Shalt Be King of Consistency" or, in a contemporary translation, "You should be an asexual leader in consistency." Either way, consistency is super important in the blogosphere. Any store would go out of business if it promised regular hours only to open once in a blue moon. Likewise, don't blog promises you don't intend to keep. The dying breath of many blogs includes the whisper "I'm going to start posting more regularly."
'Regularly,' of course, needn't mean the same thing to all bloggers. I regularly post every day, but for someone else one post a week may suffice. My recommendation, however, is that you don't post randomly, but regularly (interestingly, 'random' is a blogger buzz word so it's not surprising that bloggers often break this commandment). If you find yourself blogging about once a week, pick a specific day and claim it as your own. Is it Monday again? Post away. Or do a Drury and take Tuesday. Whatever. Tell your readers when you're open for business and then make good on your promise.
In my observation, most bloggers should pick 1 day a week and claim it as their own. But if you're up for it pick more than 1 day (the more days, the more traffic). Just be consistent. And, just for your information, here are the stats from my blog showing what days have the most blog traffic: