A the very least, my rule of thumb is “long pants and a collared shirt”. This can include polo shirts, jeans (clean and without holes), and my tennis shoes (which are grayish-brown, so they don’t stand out). I may also wear black loafers or cowboy boots.
I feel more appropriately dressed if I wear an Oxford shirt and dress pants. I wear a coat and tie when I usher.
I always shave and use cologne.
What about you?