Start by doing a good job, but just because you’re doing a good part time or full time job well, do you really want a promotion?
The increased pay might not make up for the increased workload. If you’re still interested in climbing the ladder, act now: A promotion is easier to get when there’s a job vacancy, but you need to state your case before the spot opens up.
Make sure you have glowing performance reviews, obviously, preferably in writing. Make sure you know the current market value of your position and where possible try to get recruitment consultants to back this up, again preferably in writing!
It’s also important to understand that promotions are usually decided by someone two steps up the ladder than you: You’re giving your immediate boss the necessary ammunition to convince their boss, so be prepared to articulate your assets and address your skills, whatever you do, don’t simply slag another employee off, it won’t work! Believe me I’ve conducted hundreds of interviews for internal promotion. Base your case on your future value, not on what you’ve already done, and be clear that you want new responsibilities.