Do something great, and then talk about it
Most everything we do in life is a form of marketing. Convincing a spouse or a co-worker of an idea, using our daily work to make a little bit of difference, even (especially, rather) curating our careers. When you update your resume or add an item to your portfolio, that's marketing.
So why is this so important? I already did the hard work. Shouldn't that speak for itself? Absolutely not.
Washing our hands today is an "of course" kind of thing but it wasn't always the case. Ignaz Semmelweis, in the 1800's, noticed a correlation between doctors who washed their hands and mothers that did not die in child birth. He did the work. He collected the data, he wrote it up for everyone to see, plain as day. What was the response? Backlash.
Ignaz's reward for doing the hard work (and only the hard work), was to die in a loony bin days after a harsh beating. It was years later, well after his death, that the industry started paying attention.
Proper marketing of an idea, your idea, is crucial to getting it to the right people. Facts and data alone are never enough.