Make your own citronella candles. Citronella is a tried and true mosquito repellent. If you make your own candles, you can save money and also add a couple of extra scents in case the uncut citronella smell is too strong for you (or overwhelms the scent of grilled vegetables or S'mores.) You can find a tutorial on making citronella candles from free and inexpensive materials on the Garden Therapy website.
Decorate with basil centerpieces. According to the Accidentally Green blog, the fragrance of basil wards off mosquitoes. To get the benefit all season long, consider planting containers or even a whole patch of basil near the deck where you entertain outdoors.
Move water features far from the fun. While that gurgling water fountain or designer bird bath can set the tone for a summer gathering, it could also draw mosquitoes (and that ominous whining noise they make). To keep the mosquito population at bay, consider rearranging so that none of their favorite breeding grounds are anywhere near your future party site. "Mosquitoes breed in standing water and don't like to travel far for food," Better Homes and Gardens explained. "If you have a prevalent mosquito problem, look around your outdoor space for the breeding ground. Birdbaths, ponds, and even a little pocket of rainwater can be the culprits. Flush water regularly and you should outsmart them."
Burn coffee grounds. Another GH tip for keeping mosquitoes from putting your guests on their menu: coffee. Light a little plate of used grounds so they smolder. The scent is pleasant enough and will keep bugs, including mosquitoes, out of range of party guests.