MOH here (and pictured to the right) just popping in to give y'all a recount of how things went down at WW's bachelorette party in Vegas.
In kind of went in several phases, I'll save you the trouble of the details but rather highlights of what to be prepared for (which I was) and questions to ask yourself or things to expect.
1) Know your bride (duh) when planning a party listen to requests and if you have known her long enough you should be able to get the "vibe" down pat. Although bachelorette's are typically a surprise, I don't think the whole thing should be, I mean it's this girl's wedding and shame on you if you should happen to make the wrong decision on venue, dinner, games, outfits, WHATEVER keep some things under wraps, but if you need feedback on something - ASK for it.
2) Herd people. Attendants to bachelorette party can vary from 7-20 people - all of whom do not know each other. Start email chain of open communication or create an event on Facebook so people can talk to each other and get a conversation going before the party.
3) Check in, like, A LOT. People will typically ask you a lot of questions, (especially about cost) which you may not have the entire answer to, keep following up with people to let them know what's going on (waiting on xyz, should be hearing back from abc, etc) to deflect the possibility of a cancellation. (Out of town bachelorettes like Vegas are tough, especially because of travel expenses for the individual, hotel stay etc. the in town ones are too small scale at times and could leave the bride with a less than desirable "event" feel.)
4) Be flexible - don't kill yourself over what your itinerary (oh and BTW HAVE an itinerary for events for the weekend with venues, meets, times, etc and SHARE them with the party) make sure that the things that are most important to happen (games, strip club, dancing, dinner or whatever) - actually happen and smaller less important ones can be rid of accordingly).
5) Props - definitely fun, we passed on the whole "penis" theme with the exception of straws and went for a more fun going out attire and accessories so the bride didn't look the fool and was not afraid to take some pics.
6) Take feedback and listen to others... but at the end of the day the Bride trumps the majority. People tend to have eclectic friends, some who don't party some who party to much and when it comes to things like venues and activities some might be more willing than others, instead of answering questions or requests prevent such things by letting people know BEFOREHAND when sending itinerary that this is what the bride wants to do, loves to do, is excited about etc. I remember a few moments in Vegas when a couple of folks tried to move the party and came up to me for executive party movement. After a few nos I finally said, "WW wants to stay here." BAM! Just like that, dissolved.
7) SAVE UP!!! You *need* need to have several hundred dollars saved up or a clean credit card when anticipating bachelorette party, you'll have to cover all expenses keep receipts and later divvy up the tab among the crew (KEEP YOUR RECORDS.)
8) Be a spin master, if anything negative comes up (drunken brawl - oh wait, that was me actually hehehe), someone gets sick, passes out, or what have you. Be calm cool and collected, laugh it off highlight the bright side, after all the last thing you want is that one bad thing, ruin the weekend and be the only thing that the party and the bride walk away remembering.
Oh yeah and take good pictures, videos, and plan for back up peeps (bridesmaids are good for such things). Know your supporters.