There are some good answers elsewhere on this forum. All you really needed to do was look through similar threads already posted, like this one:
It is sort of obvious, but great art style and visuals will help get people to notice your game, and good gameplay and game content beyond that will get them to keep playing.
Also note that statistically, the more games a randomly selected developer has released in the past, the better the odds of a new game from that developer doing well, by a fairly big margin, vs. a game from any randomly selected developer with a shorter track record. I am not sure if that pattern has more to do with the improvement in the typical dev's skill level over multiple projects, or the fact that they've slowly built a community, or maybe, the simple mathematical reality that bad developers tend to fail commercially and then give up quickly, i.e. it may simply be that good developers usually last longer and the really bad ones get filtered out?
Or it may just be the Rovio phenomenon - Rovio making 20-odd little mobile games (yes, on phones predating the first gen iPhone) before they hit gold with Angry Birds. But it wasn't accidental, they leveraged the revenue from each game to make the next one bigger, more polished, and more effectively marketed as the ever changing target-platform phones started to be able to run better and better quality games. Angry Birds wasn't indie, it was from an established developer that didn't have an accidental hit at all, but a mathematically calculated, strategic one backed by hundreds of thousands of dollars in carefully and cleverly allocated social media ad push getting it to the top while the market was not yet saturated. Then sadly, they milked it and had no really new good ideas for the next big thing, they were like Zynga, one cynical innovation in freemium design, being turned into dozens of variants of the exact same pile of broken garbage. With occasional exceptions ripped off with zero meaningful improvements, from actual indie developers' games nobody has really noticed because those indies couldn't spend their way into the mainstream like the knockoffs could. Yeah, I despise the people saying I should make the next Angry Birds, firstly because I don't really like Angry Birds very much, and because it is not indie. I want to make something bigger, better, deeper, and most likely, nobody will notice it. But that is how the industry works, a lot of lame crap is now becoming hugely successful simply due to manipulative marketers and a frequently lazy playerbase which refuses to spend a couple $ on a great game and instead downloads freemium stuff that is inherently broken and never seems to connect the dots on this... that freemium games are almost 100% garbage.
But whatever... the basic deal is, a lot of people are struggling with this. They want to know how to get to a successful game release. But truth be told, you won't make money as an indie game dev. Don't be upset by that, it is just how it is. Twelve indie games a year become hits, out of thousands, so it is kind of a lottery really, and you will never be the winner of it, nor will I. The market is saturated with indie stuff already. So unless what we are doing is exceptional, it won't stand a chance of being noticed by the public, and even if it is genuinely outstanding, it is still unlikely to be a hit.
Yeah, we can aim for the support positions like asset pack creation now that the indie gold rush is over, but even that clearly is difficult to do successfully.
I know, I have 1600+ seamless textures and overlays/decals, 160+ video VFX elements, 120+ 3d assets, split across almost ten different asset packs, and they have sold, about 30 times in all, which is amazing, but nobody has rated even one of them so it is getting hard for the development of them to be much worth continuing past 2020.
They will go on sale again together in a bundle for just $1 total, on Labor Day Weekend 2020, and I would love to see about $10+ in sales this time but that is unlikely as no sale I have ever run here has actually made that much. I would love for someone to rate them but that is even less likely. It is okay. I will just keep at it.
Because I am kind of out of other better options right now.