For an online casino, I look first if it's legit/trusted casino with good promotions, deposit bonuses, fast deposit and withdrawals. good customer support that can answer all my queries and concerns quickly and of course the loyalty rewards that will make me stay or stick with that casino because I know that they give good perks and benefits with their players.
You actually have a good criteria which you do look out for but one which I think you shouldn't place at priority is promotion and deposit bonuses because even scam projects can be promoted very well and you will not suspect that it's in any form fraudulent and isn't a good project to follow up although their promotion last within a short period and after they must ha e reached their target audience they may stop the promotion. Some Gambling sites can actually be fraudulent in their activities but yet the may have good and nice looks when visited so you don't get to suspect they carry out such acts.
For good sites where you can be sure to be safe both with your funds and identity, check out the gambling sites been advartises here on this forum and you will get to find some good ones that you wouldn't have to go through the stress of further verification to be sure about their authenticity.