Lay the picture frame face down in the middle of a stack of brown packing paper, and, using a few sheets, wrap it in the same way you would wrap a gift. Neatness isn't important: just make sure it's wrapped tightly. Use plenty of tape to ensure the frame is secure. You can wrap particularly delicate frames in bubble wrap before using packing paper.
Even though the frame will be put into a box, it's a good idea to label it once it's wrapped. You can indicate which picture it is and to which room it belongs in your new home.
Next, start preparing your mirror box. Generally, a mirror box is made up of two pieces that fit around the frame and can be adjusted to whatever size you need.
Take one section of the mirror box, and stuff some packing paper into the corner and sides of it. This will give your frame some cushioning. Do the same with the other side of the box.
Next, slip the frame into one side of the box and press it firmly into the paper. Add some extra paper around the frame if necessary. Then, slide the other portion of the mirror box into the first and over the frame. Push the two pieces of the box firmly together to ensure the frame won't move around. Tape all the way around the top and bottom of the box to keep the two sections together.
You can pack multiple frames in a single box if space permits; just make sure there's plenty of cushioning in between frames. Mirrors can be packed using the same method.
If you're packing a larger frame or mirror, you may need to use four sections of mirror box. In this case, after padding each section with packing paper, slide a section of box over each corner of the frame. Use plenty of tape to secure it.
Always remember to label all your boxes with their contents and destination. That way, you or your movers will know where to put each box in your new home.