Creating a tentative guest list for your wedding is one of the first steps in planning your wedding after you get engaged. Knowing approximately how many people you are planning on having is going to dictate your budget per head and the size venue that you’ll need. Before you start visiting venues, it’s a good idea to sit down with your fiancé, parents, future in-laws, and anyone else who needs to have input on invite list.
http://www.theoverwhelmedbride.com has created this handy guest list flow chart to help make decisions on who to invite and who to cut. It’s not perfect (and it lacks a mention of family members that are obligatory invites) but it can be helpful in making some tough decisions.