I want to throw an end-of-school summer party, but I don't want too few or too many people there. What should l do?

First, determine the exact max number of people you want. This depends on many factors: budget, capacity of the location, how many people you can keep in line, etc. Next, make a new list of all the people you would hope to see there, ignoring your max for a moment. Next, compare the two numbers. If you have fewer than the max, you're fine. If you have more, you'll have to cut some people. Send out personal invitations, by name, so they know they can't just bring more people. If you feel bad for cutting some people, consider a pre-party, or an after-party at a bar where everyone is welcome and pays their own way.