Well, we're assuming you have a game made and it looks decent or has some aspect of it that stands out and makes people interested in playing it. And if you did that, that's the first step and quite frankly the hardest.
Once that is done...
-Try setting up a blog or site or some sort of online venue to promote the game. Not necessarily a high cost one but (something) if possible.
-Have a trailer posted on Youtube for your project.
-post screenshots on the game page so people can see what your game looks like.
-post those images on Instagram, Pinterest as these two social sites are especially image focused.
-tell friends, family locally and on any other frequented social networks. Maybe print off a few little business card type things with imagery from your game and a simple URL so they can find it online, and if the URL cannot be simple, then use a QR code maybe.
-Encourage ratings of your game, ask for feedback and/or reviews on the game page and you're more likely to get a few people doing so. It will establish trust from future players and will also help in itch rankings maybe.
-Discord, set one up maybe for your project to build community and answer questions, and have a banner signature linking to your game in any forums, bulletin boards you are established in.
-if your game is a paid product, obviously, then consider a free feature limited demo so people can try it. Also if it's a commercial effort, you may seriously consider paid ads on some limited scale. If you can fine tune them enough to make the resulting sales exceed the ad spend then you can just cycle money through and end up when a huge phenom.
-There are also ways if you don't have a marketing budget to harness existing playerbase as your best marketing option. Like a contest in which people submit fan art and the top five get a free copy. Or affiliate selling systems, which are not something I think works on itch but I haven't actually researched that, in fairness.
-Consider building up revenue beyond the game itself. Ads on the site if it's a browser title, maybe crossposting to adshare sites like Kongregate, Newgrounds if that makes sense. Or selling extras like OST (soundtrack), artbook and making of materials etc. Or later DLC, addons. All of these are established tactics. There are many ways a game project can generate income. But my view is don't be excessive in monetizing things, I try to underprice personally and am a player, not just a developer so really dislike ads interrupting gameplay. Sometimes treating players well and respecting your audience will work out great for you, too - as it builds community and good will that can make for a sustainable business longer term. Plus I just dislike being a jerk.
-Consider selling or exchanging skills and assets. Music tracks, pixel art, 3d stuff, textures, sound effects, software tools and plugins. There has to be some part of game dev you are good at and if all else fails, and nobody plays your game then there may be some critical aspect of the game that isn't grabbing people and in fact is turning them away from being interested. Graphics and art style are the things that tend to grab attention initially, and well built gameplay gives the game longevity for players once they find you. If the graphics, sound or code is a weak spot and you have no clue how to do it well, consider trading resources with someone who has complementary skill sets, you help fill in a few gaps with their project while they help with the gaps in yours. Or you can just sell game assets widely for the sake of it making that a core product, as they're definitely valuable to people.
I have a few games moving slowly forward but mostly people are excited about my asset packs and find those to be why my profile is valuable - thousands of asset files in all, tons of PBR seamless textures, VFX overlays and decals, 3d asset packs. More arriving very soon.
matthornb.itch.io - I have a bit of credibility in discussing this topic, as 10,000+ individual people have loaded 100,000+ pages on my profile, already, 120+ followers. 200+ sales made to date worth $400+, and 17 five star ratings. Of asset packs. I have some games inching froward but generally that's still a ways off from being ready to go. It gives you a pretty strong indication that I know how to do this.
It's sometimes a bit grindy posting batches of stuff across various social channels but it can go well. Even posting here on the itch forums now and then is marketing in some sense as long as that visibility gets people to discover that your work exists. So at least you did that, and that is most definitely a start.
Good luck!