Long time lurker here, so here is how I pick an online casino these days. After getting burned once or twice I learned to read the small print first.
Licence comes first for me: see which authority is listed in the footer, because some sites quietly block certain regions. Next come deposits and withdrawals: card, e-wallets and bank transfer should all be there, and the withdrawal limits need to be written clearly.
Bonuses are the tricky part. Anything above 40x rollover is a red flag for me, and the bonus usually expires in a week or two. A decent independent write-up with the current terms is worth a read here [url=https://guidehub0ef599.omeka.net/items/show/40]Trino Casino bonus[/url] 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: slow or scripted answers usually mean trouble later.
Anyway, that is my routine. Only play with money you can afford to lose.