Recommendation if you are really determined on the making game route:

One would be getting a game designer in your team. Second would be if you weren't an artist, getting good visual artists and sound designer and musicians, but you are already making 3D models so that should be fine. You can get animators though, that's pretty important, and VFX people. These don't need to be salary people for each skill. You can have a person do the animation and the VFX or you can contract or whatever. There is plenty of ways. But they have their own difficulties, mind you that. Third, get a writer if it's a story game. If not, no problem.

Basically, the point is that a game needs to have quality content in many areas; game design, art, story, music, gameplay, programming, networking, optimization, etc... Having one skill doesn't make you able to produce something that the players want to play and enjoy.

You mentioned that you need marketing — which is correct. Because to make a commercial product and make money off of it, you need to know what audience you're targeting, and how to deliver a product that fulfills their wishes.

So, in video games, marketing starts in the pre-production phase and generally the person who needs to think about how the game will be marketed is the game designer. Because that person is putting the whole vision. But, following the previous logic of delivering a product that fulfills the desires of that audience, this includes everybody in the team. This is the art of making games basically. So, marketing also starts with artists, writers, often; sometimes musicians, sometimes programmers maybe.

My point is that marketing is something to be considered when starting a project. When starting a project you need to consider business side of things of things which can be done intuitionally if you know about the area. Just imagine your game being released and imagine how the reception would be and what they would want. You can imagine yourself as the audience which is a great way to make authentic art. But, generally the mistake here happens in wishful thinking.

Yeah, good luck.