Timing is everything! Especially when the heat keeps you from enjoying the outdoors. Plan your pool party for mid afternoon (3:00 or 4:00 PM). This will allow the party to continue on into the evening. Summer night swims mean you can swim without getting burnt to a crisp and also give a cool setting with the right lighting.
Lighting around the pool creates a cool atmosphere at any outdoor party. String lights are inexpensive and can be used all year round and for any occasion. I would suggest metal lights if you plan on leaving them up for the summer. Paper lanterns even under patios can be damaged by rain and winds. You can even get colored metal lights like these that I found at MarthaStewart.com
For extra color you can add paper lanterns in varying sizes and colors.If you choose colored metal string lights go with white lanterns and if you decide to go with dark metal string lights, use bright vibrant colored paper lanterns. This will keep your colors from clashing. Organize.com
These cute pots are a great way to decorate tables. Krylon outdoor paint helps personalize according to your party colors. Fill the pots with whatever flower or plant you wish. Shells and seastars add to the pool theme.
Silver plastic cutlery and plastic margarita cups are inexpensive and fun ways to spice up your party. Silver cutlery looks like real silverware but it's actually plastic, fun ideas for guests to use. Plastic margarita cups let you have your favorite summer drinks but in safe cups that keep broken glass out of your pool.
Food and drinks are completely up to you so be creative. Steak and chicken skewers, fruit and cheese platters and fruity coctails are always a hit so experiment with those. These are very simple ideas that let you think out of the box and make your party unique! Enjoy!