It's difficult to hear the song "Surfin' USA" without imagining a sunny beach and big waves. Use props like surfboards and beach balls to bring the ocean to your stage. Dancers can wave the surfboards over their heads or place them on the floor and pretend to catch a wave during the dance. Incorporate a beach ball, by having dancers throw to each other in patterns while they dance. When using props during group choreography, you'll need to make sure everyone is holding and handling them in the same way to ensure uniformity.
If the setting is appropriate, you might consider having your dancers perform in bathing suits with board shorts and tank tops over top for modesty. You might also dress them in brightly colored T-shirts and shorts that look like something you would wear at the beach. If your dance is simple and basic, performers can wear flip-flops or sandals. Otherwise have your dancers perform barefoot or in neutral-colored jazz shoes.
Create choreography that illustrates the song lyrics. You don't have to act out the whole tune literally, but you can incorporate specific gestures into your dance steps. For example, when the song talks about "huarachi sandals" the dancers could kick their feet out or hit the soles of their shoes with their palms. During the lyrics "bushy, bushy, blonde hair-do" your dancers could place their hands near their hair and move their head side to side while twisting their feet back and forth.
Use the catchy tune as the inspiration for a fun summertime story you can tell through your dance. Have one or two dancers play "surfer dudes" trying to get a beach full of people to take up surfing too. At first, most of the beach-goers might be doing their own thing like playing with a beach ball or miming building a sand castle. As the dance progresses, have more and more dancers pick up surfboards and join in the surfers' dance. This idea adds an extra dimension to the use of props and "acting out" the song's lyrics while engaging your audience.