Have you actually done anything promotion-worthy?
- Stayed later than necessaryIntroduced initiatives to get that project finished byimprove the deadlineorganization, such as researching new tools to help do your job better/cheaper/faster? Better still if you do this with your own motivation, without being requested to do this by management.
- Taken extra time to mentor/assist more junior colleagues, or put extra effort into team-building activities?
- Introduced initiatives to improveHave you been working on educating yourself and developing your skills so that the organization, such as researching new tools to help do your job better/cheaper/faster will benefit from them?
- Do you feel that you could help the organization better if you were in a senior position, maybe with your excellent system design/architecture skills, or your great ability to manage other developers and manage projects? Skills that aren't always in use in more junior positions.
- Have you been working on educating yourself and developing your skills so that the organization will benefit from them?
- Are you so skilled and valuable that other companies are trying to lure you away and a promotion is what will get you to stay (not a great reason but it might count)?
- Put in extra effort to ensure that tasks are finished when there are hard deadlines? Not that excessive overtime is a good way to get a promotion, but it's one way for an individual to demonstrate that they are willing to put in an extra effort when needed (and I really don't think overtime should be done at all unless it's a hard deadline and the need to do overtime has already been discussed with management). It can distinguish someone from their peers who simply walk out the door at 5 PM even when major deadlines are looming.
...Or do you just punch the clock from 9 to 5, and you are looking for more money?
You have to give this person a reason to give you a promotion. Think of it this way: if this manager has to justify the promotion of you instead of someone else to their manager, what would you want them to say? What benefit does the company gain by giving you more money and more responsibility (assuming the promotion comes with more of both, which is the usual case, but not always)? Is it worth it to them?