The best advice I've heard about keeping a notebook or journal is "Don't overthink it, just use it."<p>Mix your ideas, data, todos, and everything else all together. By nature of a notebook being composed of successive pages, your notes will be naturally organized by time through append-only operations.<p>You'll find your important stuff by folding down the page corner, frequently flipping through it, or adding bookmarks/sticky notes; no index required.<p>Anything more is getting sucked into the analog version of writing your own blogging engine/static site generator.