Hey, I thought I would throw in my two cents on this, though I don't make games for my job, indie dev is just a hobby for me.
Making a living from indie games with no experience in the games industry is like climbing Everest backwards in just your underwear - damn near impossible. I don't say this to put you off, just to be realistic.
If you're going to make simple mobile games and publish them yourself - the only way you'll make a living is if it goes viral and has an original/creative/addictive enough mechanic to keep people playing. Even studio games fail at this sometimes because the market is so oversaturated.
My advice would be to look at the truevalhalla.com blog. Matthew makes HTML5 games and licenses them to different mobile publishers and game portals, these kind of licensing deals give him a regular income, though as you will see, they are declining and he has had to concentrate on other things to maintain his income. It's still very inspirational to see it CAN be done.
For more complex titles like strategy/rpg/adventure, most indie developers will save money from another job, e.g. software development, to have enough to support themselves for a year. They then design a game, code it, start marketing it, build a community and audience, test it, polish it and then release it via Steam, GOG, iOS, Android, whatever the chosen platform is.
If it's a good game and you have marketed correctly, you will make some initial sales - hopefully enough to move onto your next project straight away. These sales will drop off quickly and you'll get some occasional spikes through Steam sales or DLC over the next 12 months.
(It's key to note they will do this in a team of at least two people, doing it solo will double the time - 2 years at least. It's a lot of work, not just the coding, art, sound and music but also the business admin, marketing, networking, distribution, playtesting etc).
This topic comes up a lot on the r/gamedev subreddit. 95% of the community there program their games in small chunks on evenings and weekends and hold down a full time job. This is a super slow way to do it but you don't have to worry about money and if the game is viable, you could make a Kickstarter to raise enough to go full time on it.
So there's my three bits of advice - licensing deals, saving up or kickstarter!