It isnt possible to find everything I need on Google. Instead I have to take presentations, textbook chapters, videos and summarize them. I add in my own understanding and where I misunderstood for later.
Not sure if it’s common but I use tags to mark questions (e.g #Q Why does she say that) and todos (e.g #TODO read this next), which distinguishes them from normal text and can be searched for. Links make it easy to organize. Vim key bindings make it pleasant typing. Has latex (mathjax) for math.