What food options will you choose? There are a few choices here. The decision will most likely come down to the budget that you wish to expend. A full catered sit-down meal is of course quite expensive, and if you cook the food as hostess, it is a tremendous amount of work. Therefore, the choice of many hostesses is to serve basic party foods such as cake, chips, nuts, perhaps sandwiches, vegetable and dip, punch, etc. Another option is to make the shower into a potluck meal with each guest asked to bring a covered dish, but generally it's just a "party foods" type of shower that is chosen.
Will the expectant father be invited to the baby shower? Years ago this question would have produced a smile while the person asked would say a resounding "no!" Things in this area have changed as well and now men are often invited to and welcomed at baby showers. It is dad's baby, too, after all! The thing to remember if it is a mixed shower is to plan your games accordingly because all of dad's friends won't be comfortable with something like a diaper changing relay race.
Games and Prizes
What kinds of games and prizes will be offered for the guests? You should choose two or three games for the guests to play, and they should have some kind of baby theme connected to them. If this is "look at the items in this container for 30 seconds and then make a list of all you remember" type of memory game, the items should be small things connected to babies such as a diaper pin, bootie, pacifier, etc. Use about 20 items, but more if you are worried about ties. Quickly make sure your winner actually named things that were shown and didn't just think they saw a certain item because it is connected to babies. If you do a word find game, such as "how many smaller words can you get from this larger word or phrase" the larger word should have a baby theme also.
Prizes (including the door prize should you offer one) should be usable by either men or women if you are having a mixed shower. If it's a ladies-only shower, you can use things such as perfumed soap, bath items, candle, and so on. Again, your budget will dictate what kind of prizes will be given. Gifts for either gender could include things such as food gifts or gift certificates.