Part of an occasional "blogger's secret" series.
Write for yourself. Really, you are best off with an audience of one to start, and use your time and effort to write down things that you will want to read in a week or a month or a year. If you are interesting to your audience of one, you have some hope of being interesting to some other person somewhere else on the planet who is interested in you. Tip: If you have already writtten something somewhere on the net that you're proud of, repurpose it or reprint it in your blog; that can get you off to a good start.
As an adjunct to this, you can use scheduled reminder services to nudge you in the right direction and remind you about things you might want to remember in the future. So write that note to your future self, and then publish a pointer to in in the future, so that you'll see it again.