Blogging is easy. All you have to do is write twice a day without any direction and stay on target until you find out what the target was.
Everyone who writes a blog struggles with the tension between staying on focus and writing whatever you damn well please. Without an editor to nix your worst impulses, you can easily go far, far astray from whatever initial impulse brought you to writing and whatever attractive topic led you to have readers.
A useful mechanism of self-guidance for me is to ensure that every post fits into at least one existing category. It doesn't help that I have to date created two hundred and thirty eight categories into which something might fit. That at least is honest; this weblog doesn't have one narrow focus, and it's been running for ten years, so some divergence of interests is not just anticipated but expected.
For an illustration of the simplicity of this approach, see Dan Cooney's painting "The Simplicity of the Semantic Web". (All rights reserved, used with permission.)