Yes... I kind of make a living making these. But... I'm not so sure it makes sense to enter the market now, it's in decline (introduction of Facebook which butchered the market, consoles with access to net, invention of mobile phones), it's basicly nothing near what it was before. The maximum you can realistically expect is 500 daily players each making you $1/month on average (assuming you did everything right, are dedicated & hardworking, got a unique idea, very good execution, etc).
Aside from that... the typical marketing, advertisment, advertisment and advertisment one more time.
Nope. Can't use advertising for these games, ARPAU is too low to afford it
You need to relay on word to mouth.
Plus, you don't really want casuals, thay were eaten by Zynga and other monsters, so you need to go for hardcore, and advertising does not work for them.
Of course there always are exceptions, I just described how it works from the point of view of 95% indies that make these