Ensure your celebration is a success -- and stays a secret -- by avoiding these all-too-common spoilers.
Let's first assume you know better than to throw a surprise party for anyone who is a) a heart patient or heart attack survivor; b) a control freak; or c) in the advanced stages of pregnancy. Now that we've gotten those particular spoilers out of the way, here are a few more:
Picking the wrong accomplice or -- even worse -- trying to do it all yourself. Especially if your guest of honor lives in the same house with you, you will need a partner to help you store party supplies, track RSVPs, decorate the party venue and ensure that your honoree shows up at the designated time and place. Make sure this person can keep a secret -- and a straight face.
Not having a secret email or phone number for RSVPs. Designate a private cell phone or email (yours or your accomplice's) for RSVPs. In fact, you might consider setting up a new email account dedicated to party responses. Make sure the invitations specify that the party is a secret.
Not having a preparty plan for the guest of honor. Never leave it to chance that your surprisee will show up at the right place or the right time without a babysitter. Ask your partner–in-crime to plan a low-key activity, then take the honoree to the party venue following it.
Visible exterior decorations and/or a driveway full of cars. Helium balloons floating on the ceiling, crepe paper flowing through the room and flamingos in the yard are all dead giveaways. Keep decorations minimal or -- if the guest of honor is a really good sport -- have cans of Silly String to launch when everyone yells, "Surprise!" Arrange in advance for your guests to park in a neighbor's driveway or a few blocks down the street.
Not considering how your guest of honor will be dressed. Keep in mind that your surprisee will not appreciate arriving home to a formal soiree if she's decked out in sweatpants and sneakers. Remember this as you plan the party and the preparty activity for your guest of honor, and ask guests to dress accordingly.