The document discusses some common mistakes made when developing online courses. It notes that while online course development can be rewarding, it also poses challenges if mistakes are made. Specifically, it mentions mistakes like using only traditional teaching methods, which do not translate well to the online format. Another key mistake is developing a course without clear goals and objectives. Additionally, failing to prioritize good website design can undermine an online course's effectiveness in attracting students and delivering the learning content. The document provides tips to avoid such mistakes in online course development.