One thing you need before August 21, is a set of solar viewing glasses. Do not use sunglasses and do not look at the Sun!!! NASA has a great page for getting started on getting the correct pair of eye protection to view the eclipse.
You don't need super expensive glasses as it's unlikely you'll use them much after the eclipse. I found what appear to be a sufficient set on Amazon for just a few dollars per pair.
They look cheap, and they are, but they'll do the job. Just make sure you are viewing the Sun through the filter and not off to the side. I plan on getting myself some of these.
I highly encourage you to find a way to get into the path of this eclipse. This is literally a once in a lifetime opportunity!!! There's another in the U.S. in 2024, but you never know about clouds or where you'll be at that time, so if you have the opportunity this year, take advantage!!!