highroll_klKlBeen reading this board for a while, so here is what I look at before signing up anywhere. After trying maybe a dozen sites I learned to read the small print first.
First thing is the licence: check who regulates the site, and if your country is on the allowed list. Then payments: card, e-wallets and bank transfer should all be there, and the withdrawal limits need to be written clearly.
The welcome offer is where most people get caught. Anything above 40x rollover is a red flag for me, and live tables often do not count at all. A useful overview with bonus rules, app info and payment methods is worth a read here [url=https://www.intensedebate.com/people/idz1ki5ul3]cray bet[/url] so you know what you are signing up for.
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.