So what kind of invites do you want to send out? It really depends on the feel of the party. I’m always a big fan of using e-vite (being green!), but I do have to say, there is something about receiving an invitation in person or in the mail that is always a joy.
There is so much you can do with invites. You can wrap them in boxes and deliver them, create them to resemble your theme, the possibilities are endless.
The thing to remember is that your invitations are the way people will find out about the party, so you want to set the mood of the party with your invite choice. Do you want to have a more formal party? Your invitation should reflect that (and say something on it as well). Is it a luau? Use a cut out of a Palm tree to write or print the info on.
Make sure you include any important info about the party. You can never go wrong addressing the who, what, where, when and why (In fact, if you are missing any of these things you probably should hire someone to plan your party for you- and yes, I am available, but it’s not cheap ;-).
A lot of books will tell you to mail or hand deliver your invites anywhere between 3-6 weeks before the party. In general 3 weeks is a good amount of time, but if you are wanting a large turnout, closer to 6 weeks is better. When Greg and I threw our Christmas party last year, we sent out a save the date at the end of September (you can never be too early if you want people at your Christmas party). In my opinion, the earlier you tell people, the better the chance of them making it (especially people with kids!)
Keep in mind you should ALWAYS have some form of RSVP. Either an e-mail, web page, telephone number, whatever. Some people will tell you in person and that is fine, but if you want to save money, you need to know how many people to expect. If they don’t RSVP at all, plan on them not being there. Of the people that RSVP yes, you can expect 10% of them to not show up (stuff happens, you can’t get mad about it, just roll with it). If they RSVP no, believe them.