Hyperhydrotic friggn fool here, 'specially in the chestal area.
I wear CoolMax or similar wicking polyester tees, which help quite a bit. CoolMax is now in use by the military and available at surplus outlets at popular prices. They make sox, drawers, etc. with it too.
White is by far the best shirt color, followed by any stripe/plaid that’s mostly white. Colors stain visibly; white usually doesn’t. And dark colors absorb more heat, so you’ll be all the more uncomfortable.
My default pants/shorts color for summer is a light beige called “stone,” “bone,” or sometimes “natural.” It’s about 2 licks lighter than standard khaki tan. Make sure you get 100% cotton. They can also be had wrinkle/stain resistant.
The best hats have an absorbent stretchy sweatband. Anything else is going to get soaked from the inside out.
Learn from the ancients, too: light colors in warm weather. Nothing heavy: shoes, belts, everything, must breathe. Pick up some cotton web belts. They come in every imaginable color.
The only black articles I willingly wear between May and September are formal wear (I’m a musician and willing to suffer for art).