The first secret? Put yourself in the shoes of others: if the document is too short it may not be worth the price, if it is too long it may seem not very straight to the point. In short, look for a good trade-off.

Clear headings, well-organized paragraphs and, most importantly, a comprehensive table of contents and, boom! You'll have a document that everyone wants to study. Another pro-tip: convert it to pdf before uploading for a clean look

The preview is always blurry but make sure that the position and color of the highlighted solutions do not immediately reveal the correct answer. Other community members are at least as smart as you are and will do anything to save a few points!

Quizzes, mock tests, and exams: are highly sought after if they are solved, updated, and with accurate solutions. If you have to invest the time on something, they are always worth the time.