As a general rule of thumb, if you advertise to 1000 people, 50 might play it, 5 might purchase an in-game item, and .05 may stick around long enough to become a whale.
So ultimately if you want any sort of play conversions you'll want to start building a community surrounding the game while you're in development. You'll need to be able to publish updates to as many social media platforms as possible (I'd suggest using a management app like "If This Then That"). Stick to a social media schedule, posting at least twice weekly and at most 3 times in a single day. You'll need at least one team member who's really active with the public and has amazing charisma. Hype, hype, hype! And you'll need several ways to support the cost of development: monetizing twitch and youtube channels, regularly creating products that people can purchase (accidentally make a funny joke on twitch? sell t-shirts), sell your code and assets on several marketplaces as you go along, do promotional exchanges with other development teams.
Once the game is out, promote in-game purchases and DLC. Keep the scope of your first 10 games really small so their revolving income can support your more expensive and complex games. Expect income from most games to sputter out after 2-5 years. Also, research the type of game that you're trying to build before writing any code or doing any concept art. Is it popular right now? What were the top 10 grossing games in that genre? What were the bottom 10 grossing games in that genre? Look up google keyword data and see when people search for specific words during specific times of the year. Plan to release your game when the best keywords are most often searched. Commit a percentage of all income to advertisement. Do promotions and ads when keywords are most likely to be searched. I could go on, but at some point this becomes a TED talk.