DO make the RSVP date very clear on the invitation. You want the guests to know exactly when they need to respond so they don't miss the deadline. If the date is right on the invitation, it will cement in their brains. *I missed the deadline to a wedding RSVP because there wasn't a date - I had to look it up on the wedding website. If they miss the deadline, YOU get to call them, so include it.
DO make the directions very clear. I once received an invitation without an address of the ceremony location or even a name of the venue, just a tiny nap, and it took me a long time to figure out where to go.
DON'T make your guests pay any postage to RSVP. If you can't afford stamps, find other ways to get responses.
DO make it as easy as possible for the guests to RSVP. Pre-addressed and stamped envelopes with the included card are ultimately still the easiest way for the guests. Other easy ways are emailing, and e-vites, website RSVPs.
Is it the guest's fault or yours?
Ultimately, as long as the information is available, the guest should take responsibility and find out the info - but it's so much more helpful to them when everything is clear - and it's less headaches for you later.
DON'T send out a wedding invitation via a Facebook
Event or some similar medium. Not only is it rude, but it's very easy for people to completely overlook events like this. I get invited to so many events that are sent out to every friend on the person's list that I don't even notice when a new event pops up on Facebook. Remember, if it's an important occasion, it should be treated as such.
DO make sure you include the names of everyone you invite on the envelope (if you have two envelopes, doing it on the inner envelopes is enough). I didn't make it clear on one of my invitations who was invited, and it caused confusion and hurt feelings. I've gotten invitations that were the same way, and to this day I'm still not sure if I was invited.
Did you know?
Did you know that it's actually considered bad etiquette to include your registry information in your invitation? While you may worry guests won't know what to do about gifts, you make actually find that you'll get a lot of cash that way.