An invitation needs to have the following information:
* Location of the party and a map if necessary
* Starting and ending time
* Whether parents/children are invited
* Special activities that might require special clothing
* Your phone number

More tips:
* Include A Landmark - this makes it a lot easier for guests to find the location
* Include A Landmark - make sure that caterer's, etc. have explicit directions
* Use a checklist so that you know who has received the invitations
* Phone to check to see if some haven't received the invitation
* For those who haven't made a commitment to attend, ASK for a commitment
* May need to provide a timeline for those who haven't made a commitment
* Have someone quiz you with respect to details