Well many ways to earn "free money" from gambling site...

1. Faucet
Alot gambling site offering faucet. But like we know the faucet amount is very small, just allin your "free money" in high multiplier, if you lucky... BOOM you will earn good profits (but its like 1:10000 bet, so definitely it's still WASTE TIME)

2. Rains
in a few gambling site, usually rainbot (or anything like that) will giving free coins to players who active chatting every 30-60 minutes... just collect "free money" from rainbot. But it's still WASTE TIME, usually i just came and chatting in spare time (not all the time).

3. Tips
You dont need begging for tips, if they (other players) think you is funny, good guy etc etc. I think they will giving you tip (But do not expect to tip. Because if you expect people to tip you, it's just like a beggars).

The points: gambling is just for fun, So less precise if you make gambling as a source of income, moreover just with faucet, it's looks just WASTE TIME.