Start learning digital marketing

Hi all, I want to start in digital marketing or marketing in general as I am quite interested in it and want to pursue it as an additional skill, and hopefully earn a side income from it. Any suggestions on how should I go about it? I am reading up on things online and auditing a digital marketing course from Google. Apart from this I am trying to reach out to local vendors and try to offer digital marketing services like running ads for them (for free) and if required create a landing page for them (for minimal cost) if they don't already have one.