The first stage to putting on a Waiting for Dollars event is to find a local restaurant that's happy to host it — you should find that they appreciate the extra business it's going to attract, and of course it's all for a good cause too.
Your group's role is to take over the duties of waiting on tables and bussing dirty dishes in exchange for collecting any tips you can. It's probably a good idea to have some experienced wait staff around to help give you guidance.
Upon hearing that their tips will be going towards a good cause, most patrons are likely to be more generous with their money and may well pay over the traditional level of fifteen to twenty percent.
See if you can choose one of the more popular restaurants so you get a decent turnout and plenty of cash for your chosen cause. You can advertise the aims of the event around your area, and you might even want to work with the restaurant owner to produce a specially themed menu for the evening. You could ask if the restaurant would be willing to make donations too (say $1 for every meal ordered from the special menu).
As for your group's volunteers, remind them to be polite, fast, and accurate — and do your best not to break any plates!
See more fundraising with household chores ideas here.