How to find roles in pe/vc/ib

Hey All, 

I'm a recent graduate from a state school and have been working at a financial services company after college. I started off at an investment banking capital markets company but only stayed there for less than a year. I've been trying to apply to ib/pe/vc roles and get on the buy side in a big city and move, but I don't see any roles posted on the major job sites(Linkedin, Indeed, Glassdoor). Where can I find these roles and apply. 

I've tried to cold call and cold email firms from their websites but usually they are small firms not looking for people. I see all these people get interview and roles at major firms but I was wondering how they find the roles. Is it just applying on the company website? I really need a brand name on my resume. 

Thanks