Some common mistakes to avoid when starting an online business include waiting too long to launch, trying to do everything yourself, not bothering with any online marketing, hiring the wrong people, ignoring the legal stuff, forgetting about discipline, not knowing what your customers want, not being different to your competition, not knowing your audience, worrying about insignificant details, spending too much too quickly, undervaluing your product or yourself, ignoring your customers and underestimating the time and effort it takes to succeed.