I have increased my salary by at least 30-50% every single time I have quit to go somewhere else.
My advice to anyone, especially anyone starting out today in fields such as project management, marketing, finance, online, ecommerce etc is, get a job, get 2 years on your resume and quit for the next thing.
Start planning leaving at 18 months. Write an email to yourself from your personal email to your personal email about projects you've been a apart of, reports you write, new tasks you do.
Even if you only play a small role on a large project, write that down 'I was part of a multi-team project to secure/achieve/deliver revenue/new client/new technology'.
It really simple, companies have good budgets to hire new people and nothing, or very little, to retain staff – take advantage of that. Go become a new hire and stop waiting for someone to pay to keep you.