Measure the size of the tea pot you wish to cover horizontally from the tip of the spout to the tip of the handle. Write this measurement down on a piece of paper.
Measure the height of the teapot from the top of the lid to the table the pot it setting on. Then measure the height of the teapot from the tip of the spout to the table and from the top tip of the handle to the table.
Make marks on the tracing paper to indicate the measurements of the teapot. You should have one mark for the top, two marks for either side horizontally and then also from the measurement you took from the spout to the table and from the handle to the table and one mark for the bottom.
Draw a curved line connecting all the dots except the one on the bottom. Draw the curved line so that it extends below the mark on the bottom. Use a ruler lined up with the mark for the bottom, and connect the ends of the curved line with one straight line. You will have something that looks like an over-sized half-moon shape.
Stack the two placemats together and lay the pattern on the top placemat. Pin the pattern to the placemats just below the line you drew.
Cut out the pattern by cutting through both placemats one inch above the line on the pattern. This will be your seam allowance.
Turn the placemats right sides together and pin about 1 inch from the edge of the fabric all the way around.
Sew the two placemat pieces together, leaving the bottom edge open so the cozy can slip over the tea pot.
Turn the bottom edges over and hand sew in place to make a finished edge along the bottom. Finish the tea cozy by turning right sides out and ironing flat.