What's some good Marketing Practices?

I’ve never made a proper full fledged game, or know any marketing strategies at all, I don’t even know how to run a business, and I’m wondering what are some good practices for a beginner?
I’ve made a couple trash games to get a good understanding of studio and scripting, but now I think I’m ready.

I’m sure it isn’t “Rocket Science” and has some “Common Sense” but I just want to make sure I got everything down before I go all in and try to make something.