punter_vworLong time lurker here, so here is my short checklist for choosing a casino site. After a few bad experiences I stopped going by ads alone.
I always start with licensing: find the licence number and look it up, and if your country is on the allowed list. Next come deposits and withdrawals: card, e-wallets and bank transfer should all be there, and cashout times should be listed up front.
Bonuses are the tricky part. Anything above 40x rollover is a red flag for me, and some games count less towards it. A good recent review that covers all of this is here [url=http://weblabor.hu/tagok/122103]bonus at Trino Casino[/url] so you know what you are signing up for.
I play almost only on my phone, and a good site loads fast and does not log you out every five minutes. Support matters too: a real human reply beats a bot loop.
That is about it. Only play with money you can afford to lose.