There are many photography tips that can help you get memorable records of your trip. Don't do to much in one day - If you only have one day to visit waterfalls, don't rush around trying to get in as many waterfalls as possible. Pick a few and spend your time relaxing near the falls instead of in the car. Well, maybe not. But remember to be courteous to other waterfall visitors.
Most people visit waterfalls for peace and beauty.
Swimming, sunbathing, and large groups disrupt that peace and can ruin someone else's trip. In particular, photographers can go crazy trying to get a shot of a waterfall when people are climbing on or swimming around a waterfall. This is not to say that swimming should not be done. However, be reasonable and aware of others. Bring water since it isn't advisable to drink stream water.