gambling is not a way to earn bitcoin online and even if you can earn something out of pure luck it is definitely not an stable way to earn bitcoin.
for more reliable way you have to do some jobs based on your skills. trading is one of these ways which requires some skills which everybody can learn.
Gambling will always be a good method it you have too many coins and you want to get rid of some of them.
The house always wins.
Skills are really better. But where can I learn those skills?
Gambling of course one way to earn bitcoin online, even not steady way for some people who don't know to get it.
But some people have steady income by gambling, where to learn those skills? You just need to find they who already good at it.
I could give you one of that person, check thread of US Open 2016 : tips and thought.