Raising capital for a game in todays world is no different then raising money for a movie as it's a "hits business". Find other people who have raised money and ask them who they got money from, then try and convince them that you'll be able to make them money with your game.

It's really that simple.

1) Create a list of all games you know that have raised money
2) Cold email the CEO/Founder (tip: firstname@company.com)
3) Get them on a call for advice
4) If they like you, ask them who invested and if they'd make an intro
5) Persuade the investors you're a good investment.

Outside of that, get a bunch of credit cards, ask your friends and family or max out your available credit.

If you think $1 invested can generate $1.50 - then invest yourself on credit.

That's how many people have done it, including myself.