Basically, all you need to do to get this type of shower going is to invite a bunch of the bride's girlfriends over and tell them to bring her something romantic to wear on the honeymoon.
Trust me, having been to a few, this leads to a lot of laughs and full-on hilarity when those gifts are finally opened.
Be sure to supply the bride-to-be's correct sizes when sending out the invites so that everything she gets should fit properly.
These parties are usually best kept under wraps at home or in a private room setting if you're having the party at a restaurant. In the very least, if you are in public, try to keep it inside of a booth so others aren't too bothered by the noise.