I&#x27;m using draw.io to draw mockups, it&#x27;s incredibly useful, it helps me to figure out how the interface looks like.<p>Also I use emacs org-mode to write down my notes. Usually it&#x27;s just some thoughts on the project and list of features that I want.<p>Then I start putting it together in browser, usually almost immediately, without much preparation. I just create a django project, add a test view, and start writing some html&#x2F;css. It really helps me to think, as I do that I get all sorts of ideas about the design, features that I want, and how the whole project will be structured.<p>Meanwhile, on my notes, I have a list of &quot;big&quot;, &quot;medium&quot;, and &quot;small&quot; features, ranked by importance(or in order I want to build them in). Also bugs, questions, and whatever other ideas I have.<p>But all that is just for personal projects, I haven&#x27;t yet worked in teams on anything big.