"If your mask doesn't have a nose clamp, use a paperclip or some jewelry wire or anything appropriately bendy and non-snappable, and weave it through the part of the mask that sits on bridge of your nose. Now you can mold the mask around your nose better, which prevents air from going straight into the glasses.
Make sure you fold the wire in and down and away from your eyes, or tape it so there are no sharp edges! And don't wash your mask with anything fragile."
"Sew or glue one of those green twisty things from the grocery store or a pipe cleaner or any metal wire at the top of your mask so that you can bend it to fit your nose better."