Any adult births can be planned and put together without much stress. Start off with deciding if you want to add theme to your birthday party. This will give you something else to work with. Is this birthday a millstone? Maybe the guest of honor is turning thirty, forty, fifty or older? If this is the case, base your party around this.
Start off your adult births with your invitations. Base your invite around the theme you have picked. For the normal birthday idea, then you should be able to find invites for such an occasion. You can even add to these invites with stickers or paper cut outs. Make sure you send these out two to three weeks in advance.
With throwing adult births you should decide if you want your guests to bring a gift or not. Either set a limit of money to spend and place this on your invoice, or state that no gift is needed just to bring themselves. This might bring more people to you 'party!
If you plan on serving alcohol at your adult birthdays make sure that there is a designated driver, maybe more then one. With everyone driving to your party, this is a necessary thing to consider.
You could also invite your guest's children to the adult birthday if they can not find any babysitters. Set aside a playroom or area for the party and set them up with games or a movie. You will have to have someone check on the kids, but if they are older they'll be happy with a movie to watch.
One thing to make sure of you're adult birthdays is to see it that you're a guest of honor has a great time! Most of all, make it safe, fun, and memorable for all involved.