Consider joining a small but growing startup as an employee. It's a bit of a gamble, but if you find one that grows from e.g. <10 to >50 people in 3-5 years, th

Consider joining a small but growing startup as an employee. It's a bit of a gamble, but if you find one that grows from e.g. <10 to >50 people in 3-5 years, that will be the best way to learn marketing (and sales, customer support, product, etc etc) which is not replicable through any books, courses etc. You can learn what does _and doesn't_ work, work with and learn from a team (and hopefully a good founder), and then apply those lessons to your own side project or startup.