Qualifications
To work as a server, you need to have serious people skills. Half the reason these folks came to your restaurant was to have the service experience, and you're the one they're asking to provide it.
That means to do your job right you've got to be able to listen, answer questions, and manage expectations all at the same time. You've got to be personable and relatable, and generally interested in your guests having a good time.
This isn't just about mechanics either; memorizing the menu's a great ability, but it won't make a difference if you make everything sound like it was pulled out of last week's garbage dump.
Then there are the little day-to-day aspects of your job. You're going to be pretty active all day, so staying fit helps. You need to be able to spend your entire day on your feet and not complain about it. Your employer will expect you to handle money properly, treat guests with respect and attention to detail, and above all be reliable.
If you're clocking out ten minutes into every shift because you "don't feel good," you can eventually expect not to receive any shifts at all. Won't you feel silly then?