I don't know why nautical themed fashion reminds me of America, but we have a few shores and a navy so if you don't want to look like you just stepped out of a patriotic themed store, nautical duds might be a fun (less over the top!) option.
If you're spending your 4th on the lawn somewhere at a fabulous picnic, choosing a fab white dress or grabbing some gingham for your getup is a summery way to celebrate. Or pick a playsuit in denim or linen to keep cool and party hard in.
Finally, those of us lucky enough to have the day off might choose to soak up some sun by the pool or the lake, so here are some fun options for that! Maybe I'm the only crazy person who wears jewelry and wedges to the pool, but it's so very Samantha from Sex in the City that I have to recommend you try it at least once. You'll never feel more chic.