Any advice or credible websites on raising goldfish?

I recently received an assignment to get and care for a fish of some kind. I am leaning toward a goldfish, specifically the black, pop-out eye kind. I’m still looking for the real name of the breed.

My last experiences with two betas was disastrous, leaving me nervous with fish period. So, any good advice or helpful websites on raising goldfish? I would like it to stay alive for at least a month or more…

(I have already “googled” it. Nothing but sites for little kids came up. I need some serious, more in depth information).