When I got my new job at a new employer, I was a trainee and earned 50% less than my current salary.
I can currently estimate that my colleagues earn twice if not more than I do. Our job titles/responsibilities are exactly the same. Our qualifications are exactly the same. However they have one year or so more experience than me.
Should I approach my employer and ask for a fair salary? If I do approach, how should I prepare, and what points should I make to be successful?