I accidentaly punched a 1/2 inch hole in my winge on the monokote. What's the best way to fix it?

If I'm at the field when that happens I use some 3M Clear Package Tape. Works quite well. For a more permanent fix I use some scrap covering of whatever happens to be on the plane. I cut a round piece or at least with rounded corners (to prevent dog-ears) with an overlap of about 1/4 - 3/8 of an inch all the way around. Seal it down with the iron, let it cool, then use the tip of the iron to shrink it in the center. Try not to touch the part that is already adhered or it might soften the adhesive and allow it to slip.

Electrical tape works better than one would think to patch up holes at the field. If you get it sealed down it won't come up. I also take strips of Top Flight self sticking film for field repairs.

excellent... I'm new to the hobby and the inevitable happened. Thanks for the advice.