Been reading this board for a while, so here is what I look at before signing up anywhere. After trying maybe a dozen sites I stopped going by ads alone.
Licence comes first for me: find the licence number and look it up, and if your country is on the allowed list. Then payments: I want at least one fast e-wallet option, 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 is here [url=https://www.efunda.com/members/people/show_people.cfm?Usr=martinezda692a]smash casino[/url] and it saved me some time.
I play almost only on my phone, and a good site loads fast and does not log you out every five minutes. Ask support one simple question first: slow or scripted answers usually mean trouble later.
Anyway, that is my routine. Only play with money you can afford to lose.