Signature campaigns are obviously the most successful way to make money here.
However, there are many ways to earn Bitcoin which aren't linked to the forum.
Here are a few ways off the top of my head.
Trading (Requries Bitcoin to start)
Bitcoin Faucets (Free to start)
Gambling (Requries Bitcoin to start)
Sites like primedice and satoshi bet allow you to gamble your existing Bitcoins to try to gain more. Very risky, ant often not worth it.
Working for Bitcoin (Free to start)
In my humble opinion i dont think that gambling is one of best way to earn bitcoin,It doesn't matter how much you start with, you will always end up at zero. As we know that gambling is a risky way for the player, but you know this is the the fastest way for the gambling owner to make much bitcoin.
I guess you are right, Ive never had any success with gambling. Always lost.