Whereas students reading a memoir / (auto)biography publish weekly blog posts, people making a Commonplace Book (CPB) make regular entries in their CPB.
For models of such entries, see my CPB purplemarblemajesty. Notice that the typical entry is shorter than the biography weekly posts. For your CPB project, it is more important to write regular entries than to write long ones. In your entries, write enough to be clear, specific and developed, but write in such a way and at such a length that you can maintain the habit of writing an entry every other day. On the “off” days, you can comb your books for passages to be included in the next entry.
On Fridays, I will look to see how you are progressing with this schedule of an entry every other day. As always, especially since this is the pilot year for CPBs, ask when you need to.