Baby showers are just plain fun! Planning one can be as much fun as attending as long as you keep some fundamental things in mind. Many of the "rules" that were in place for the past years and decades are no longer followed and that is actually a good thing in most cases.
One thing that is different now is that sometimes the mom-to-be wants her partner to have a part of the baby shower. This is fine now but as planner, be sure that your menu and games reflect the fact that the guest list will include the new dad and his friends. Inviting male guests is great, but then don't serve only dainty little tea sandwiches and cakes. Just expand the menu into more of a universal fare.
When it comes to games for the mixed gender shower, the guys you have invited may enjoy some of the guessing games, trivia games, or memory games, but they most likely won't enjoy guessing how many sheets of toilet paper it will take to fit around the expectant mom's tummy. (No, I didn't make that up; it's actually a favorite game for baby showers!)
Another thing that has changed is that these types of showers were usually surprise parties in the past. More and more expectant moms now prefer knowing about an upcoming shower for various reasons. Allowing her to help with the guest list is a good choice.
The guest of honor may also wish to begin a baby gift registry somewhere if she knows there will be a shower. She will be able to help with a menu as well as the guest list. Do not expect her to do any of the work for the party though, of course. She can be surprised with the games you plan. Don't forget to have prizes for the games. If it is a mixed gender party, it's a little more difficult to find proper prizes, but it will not take very long to think of things that either gender can use. (Things like a little basket of individually wrapped snacks, homemade baked goods or bread, picture frame, pens, and so on.)
There are a few things that often get pushed aside or forgotten when it comes to planning a baby shower. One thing in that category is what you will arrange by way of having the party photographed or videotaped. If you ask someone to videotape, be sure to have a copy made for the parents-to-be and perhaps a copy for the grandparents.
The timing of the shower might be another area in which your guest of honor can have a vote. Would she prefer to have a shower before the baby is born? Perhaps she would prefer waiting until after the birth so that gifts can be bought for either a boy or girl and the guests won't need to find all those green or white items that could be for either gender.
If you are planning the shower to be held before the birth, be sure to have it at least 3 or 4 weeks ahead of the due date. Most people end up choosing to hold the shower before the birth so that the parents will not have to buy a lot of baby products before the baby is born. A shower usually brings an abundance of sleepers, t-shirts, socks, blankets, and so on. It is always a welcomed thing to have those items on hand when the baby comes home from the hospital.
Assign someone to be the official "keeper of records." This often works well for a teen who wants to be involved with planning the shower. Keep a list of guests with addresses if you don't already have them; activities and food that were part of the party (for the baby book!); and very importantly, a list of the gifts matched up with the guest who brought the gift. This is needed so that the thank you notes can be written.
If your guest list (and thus the number of gifts) is large, you or the mom-to-be may decide that she will open the gifts at home. While most people enjoy seeing the gifts being opened, there simply isn't time for that at the shower sometimes (showers should generally last 90 minutes to 2 hours). As an alternative, help with the gift opening yourself or ask someone else, and they will be opened twice as fast.