Apply an "X" of masking tape over the painting's glass surface. If the glass should break during the moving process, the tape will hold the glass pieces together, preventing them from piercing and damaging the painting.
Lay the painting on top of a large sheet of bubble wrap. Fold the edges of the bubble wrap over the front of the painting. Secure the bubble wrap to itself with packing tape. The entire painting should be covered. If the painting has a large sheet of glass or is particularly fragile, wrap it in two or three layers of bubble wrap.
Place the painting inside a mirror or picture box. Fill the spaces between the painting and the box with wadded up newspaper or bubble wrap. The painting should be suspended inside the box.
Place the first box inside a second, slightly larger box and fill the gaps with wadded newspaper. The second box is only necessary for canvas paintings, as a barrier against sharp objects that might puncture the box and pierce the canvas.