You'll first need to cut your fabric. To do this, first figure out how much you want the liner fabric to overhang your box. Since you can see that my outside fabric came up a little short (that was the biggest size scrap of fabric I had), I decided on a 5" overhang. Depending on the size of your box, I think 3-4" usually looks pretty good. Once you decide how much overhang you want, double that number and add that to the size of your outside fabric piece.

For instance, my outside fabric (brown) measured 39" x 48". Since I wanted a 5" overhang, I cut my liner fabric 49" x 58". That gives me an extra 5" on each of the 4 sides.

Once you have your full piece of fabric cut, follow the same process as #3 & 4 for the outside of the box. Place your box in the center of the fabric and measure out from the corner of the box to the corner of the fabric. This time, mark the fabric at the 1" mark (instead of the 2" mark). I just use a straight pin to mark my spot.

Just as in step #5 (above), mark a straight line from your pin to each edge of the fabric, making a rectangle. I like to use a fabric chalk pencil to mark my fabric - its easy and the chalk just dusts right off. Cut out the rectangle. This is extra fabric you don't need. Repeat with the other 3 corners. Do NOT clip the corner from the 1" mark to the box (like you did from the 2" mark with your other fabric).

Once you have all 4 corners cut out, your liner fabric will resemble a cross. Now comes the sewing part. Trust me, even if you have never sewn before you can do it. I use a basic sewing machine (like this one) and it works great for all types of projects. Ready to sew? Let's do it!

You are going to fold side #2 on top of side #1, lining the edges up. Pin together. Notice that I am folding the right sides (the darker sides) of my fabric together. The wrong side of the fabric (the lighter side) is on the outside. Sew from the top (in the picture) to the bottom with a 1/2" seam allowance (1/2" from the pinned together edge). Sew together sides 3 & 4, sides 5 & 6 and sides 7 & 8 in the same way. When you are done you'll have your liner.

To finish off your liner, hem the top edge (the only edge not yet sewn). I just fold mine over (wrong sides together) about 1/2" and stitch all the way around. This will give you a finished look and make sure your fabric doesn't unravel. If you are worried about sewing a straight line, you can iron the edge down before you sew.