Tape down the top of the mask to your face (at least over the bridge of your nose) to force the air through the mask rather than up. It also keeps the mask from slipping! Gentle or paper medical tape can be easily bought next to the bandages.

I'm sighted (with a visually impaired family member) and wear glasses all the time. Been doing this since March and not getting any fogging at all!

If your glasses fog up because of your mask, try putting your mask underneath your glasses, under the nose pads if possible. Other than that, IDK.

Glasses I'm not sure, but I know some people who wash their safety glasses with handsoap to prevent fog; maybe that would work with sunglasses? If the fog relates to masks only, I've found gaiters and balaclavas to cause less fog, as well as masks with a longer metal nose pinch piece.