Long time lurker here, thought I would drop my short checklist for choosing a casino site. After getting burned once or twice I stopped trusting the big banners.
First thing is the licence: check who regulates the site, because some sites quietly block certain regions. Then payments: 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 some games count less towards it. A good recent review that covers all of this is here [url=https://www.dibiz.com/activation+dbz348aaea316]bonus at Rolletto[/url] before you deposit anything.
On mobile I mostly use the browser version, so I check how the lobby works on a small screen. Ask support one simple question first: if they answer in a couple of minutes that is a good sign.
That is about it. Set a budget and stick to it.