punter_nporLong time lurker here, so here is how I pick an online casino these days. After trying maybe a dozen sites I stopped trusting the big banners.
Licence comes first for me: find the licence number and look it up, and if your country is on the allowed list. Next come deposits and withdrawals: crypto is a plus but not a must, and there should be no weird fees on cashouts.
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 can be found here [url=http://weblabor.hu/tagok/122104]bonus at Revery Play[/url] before you deposit anything.
On mobile I mostly use the browser version, and if there is an app I make sure it comes from the official page. Support matters too: if they answer in a couple of minutes that is a good sign.
That is about it. Only play with money you can afford to lose.