First, protect your eyes. Second, protect your camera - according to camera company Nikon, you will need to use a solar filter to keep from harming your camera’s imaging sensor. NEVER look through the viewfinder of your camera when it is pointed directly at the sun. It will damage your eyes. This goes for cell phone cameras as well.
Don't get so caught up in taking photographs that you forget to really look at the eclipse. If you are in the path of totality, remember to look around at the darkness and the stars, listen for birds going to roost. Try and notice any temperature drop. You will see awe in the faces of those around you. Don't miss actually seeing the eclipse. Looking exclusively through a lens is no substitute for the real thing. Don't miss the big picture. And again, protect your eyes.