Besides protecting you and your family from mosquitoes
Usually, a porch party is quite informal. If you have good nibbles, dips, sandwiches or some soup and cold drinks laid out at a convenient spot on the porch, then you're set. But just to keep things interesting and more fun, especially if you plan to host porch parties on a regular basis, dressing up the place a bit and jazzing up some of the food would be great. Just remember, that the whole purpose is fun and relaxation, so don't go stressing yourself or going overboard with the preps just to make an impression.
For starters, hang up some decor. If you have a theme, decorate around it. Put up a banner and have some balloons-the ever-reliable and low-cost party decor. For more fun, instead of regular balloons, have those in different shapes. If you can get balloon shapes that relate to your theme, all the better. A screened porch provides lots of space for decor. A word of caution, don't block out the view and make sure decorations don't hamper ventilation. With an open porch, you can have a grill and host a porch barbecue. For a beach theme, scatter some sand and seashells collected from your last beach vacation.
Your main table where all the food is laid out could have a centerpiece. Citronella candles or an extra large hurricane lamp will do. Make sure the table is located on the most convenient side of the porch. It is still a limited space after all. You can have a table with the food on one side and on the opposite side have a mini bar. For tighter porch spaces, a large urn or long planter lined with garbage bag and filled with ice can function as cooler. Jam the ice with all kinds of drinks so guest can grab the drink they fancy.
For food, aside from the usual chips and dips, serve fruit kebobs or jello-shots. An assortment of fruit slices are colorful on the table and especially inviting on warm summer nights. For coffee and hot choco lovers, you might want to set up a bar of that sort at one end of the porch. You can set up an array of ingredients for them to whip up their own concoction. If serving food that looks a bit different than the usual fare, set up some colorful food place cards with brief description in small but readable print under the name. That way you encourage guest to try it out and they won't be guessing what's in it.
Finally, to remember the night, hand out inexpensive goodie bags. In some places, the host packs small samples of the porch party specialty foods and hands them out to guests as they leave. A small recipe booklet or recipe card could accompany the give-away so guests can recreate the dish in their own kitchens or at the next gathering.