Long time lurker here, thought I would drop how I pick an online casino these days. After a few bad experiences I learned to read the small print first.
Licence comes first for me: find the licence number and look it up, and whether they actually accept players from your country. After that I look at banking: I want at least one fast e-wallet option, and cashout times should be listed up front.
Never judge a site by the bonus alone. Read the wagering and the max bet rule, and some games count less towards it. A good recent review that covers all of this is here Revery Play review and it saved me some time.
I play almost only on my phone, so I check how the lobby works on a small screen. Support matters too: a real human reply beats a bot loop.
Hope this helps someone. Treat it as entertainment, not income.