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: check who regulates the site, and whether they actually accept players from your country. Then payments: crypto is a plus but not a must, and cashout times should be listed up front.
Bonuses are the tricky part. Read the wagering and the max bet rule, and live tables often do not count at all. A good recent review that covers all of this is here bonus at Lottoland before you deposit anything.
On mobile I mostly use the browser version, and a good site loads fast and does not log you out every five minutes. Test the live chat before depositing: slow or scripted answers usually mean trouble later.
Anyway, that is my routine. Only play with money you can afford to lose.