Do gambling affiliate is good while you gamble but I think it still need some diligence to get people join your referral, but it's worth a try if you know you can get some.
Most people actually gamble just small proportion and it is not really worth it, unless you can really get one "real gambler" as your affiliate then dont really waste your time on that
Around two years back, I was a part of a signature campaign that used to pay for referrals as well. I didn't got a large number of referrals, but if my memory is not wrong, then some 5-6 guys signed up using my referral link and I got some mBTC for that. I don't know whether there are any campaigns now, which pay for referrals. But if you have large number of quality posts here, then referral income can be substantial.