Game Development

https://gdcvault.com/play/1034535/Independent-Games-Summit-It-s

This is a joint talk with Dana Trebella and Derek Lieu about this exact subject from their professional perspectives (indie marketing and trailer editor, respectively). They both have multiple talks over the years where they explain different aspects of their day to day work. Taken as a whole, it's a solid crash course on DIY marketing.

Another talk more focused on finding your messaging: https://www.gdcvault.com/play/1025673/More-Feelings-Fewer-Features-Showcasing

If written articles are more your jam: https://www.gamedeveloper.com/marketing/how-to-market-a-game-an-introduction-to-game-marketing

There is no "marketing" strategy that will push a bad game to success.

Do some networking, coordinate with other gamedevs, genuinely be interested in their stuff, they will be genuinely interested in yours, take feedback seriously.

Any game with a good shot at success has historically looked so remarkable, so unique that they will stick out and won't need much more than a few social media posts and one or two influencers to notice it. Most youtubers have business emails. If you send it to 100 people whose job it is to discover and promote the next new hot thing and NOBODY picks it up, your issue is not marketing, you just have a bad product.

I can't tell you what's worked because I'm still in the process, but here's what I'm doing or plan to do soon:

-Demo released on steam and itch
-youtube channel with soundtrack uploads and video essays
-eye catching, engaging trailer
-promotion on personal YouTube channel
-Outreach to content creators (specifically, ones that seem like a good fit for you kind of game)
-Steam next fest/ other online game expo events
-Word of mouth/flyer adverts if you live in or near a decently sized city

If there was a silver bullet marketing strat, everyone would be doing it. I'm hoping that consistent, boots on the ground effort, diversification of marketing, and persistence will pay off.