Have you actually done anything promotion-worthy?

 - Stayed later than necessary to get that project finished by the deadline?
 - Taken *extra* time to mentor/assist more junior colleagues, or put extra effort into team-building activities?
 - Introduced initiatives to improve the organization, such as researching new tools to help do your job better/cheaper/faster?
 - 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)? 

...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?