Here’s a neat way to mount and hang a picture so that it has a clean frameless look. Sandwich the picture between a sheet of glass or clear plastic and piece of hardboard or stiff card-board. Then use tiny binder clips along the edges to clamp the pieces together. Use two or three clips on each side. After the clips are in place, remove the clip handles at front. Tie picture wire to the rear handles for hanging the picture.
Considering how thin it is, dental floss is strong stuff. Use it instead of string or wire to securely hang pictures, sun catchers, or wind chimes. Use it with a needle to thread together papers you want to attach or those you want to display, in clothesline fashion.
Before driving a nail into the wall, put a piece of tape on the wall at the site. This will prevent the paint from peeling off if you have to remove the nail, and it will prevent wallboards from cracking too.