With wikis or note taking applications, I always find it hard to get into a habit of using them. I think this is largely because too much brain space is taken up with:

    1. When should I write something here?
    2. How should I organize it?

For this reason, I'm currently trying out more of a "journal" model. The answers to the previous two questions are:

    1. Write whenever you have an interesting idea, or you get that
       feeling that something important is about to get evicted from
       your brain cache.
    2. Every note goes in YYYY-MM-DD.md on the day you make the note.
       You can add #tags to entries to track your thinking or progress
       on a particular topic over time.

I've just started this, so we'll see how it turns out. But I'm optimistic.