Resources: Embellishments and notions are available from M&J Trimming. All other tools and materials available at fabric and sewing-supply stores.
Download and print our dog coat pattern, enlarging the pattern according to size of dog. (We enlarged ours to 225 percent for a French bulldog.)
Cut out front panel with pattern placed on folded edge of polar fleece. Repeat with back panel. Cut two sleeves from unfolded polar fleece. Place patterns aside to reference as you sew.
Pin front panel to sleeves, lining up single arrows indicated on pattern. Sew "raglan" seams as indicated on the pattern by dashed lines.
Pin back panel to sleeves, lining up double arrows. Sew as indicated by dashed lines.
Trim all seam allowances to 1/8 of an inch. Sew side seam (indicated on pattern.
Fold neck opening 2 inches into coat (this fold is marked on pattern with a dotted line). Machine-stitch around the neck opening, 1 1/2 inches from the fold.
To create a channel for neck elastic, stitch around the neck opening again, 1 inch from the fold. Make a small cut in the center back of the channel you have created, and draw elastic through channel.
Loop elastic through a cord stopper. Tie elastic into a square knot, trim ends, and bury knot inside channel.
Embellish coat with iron-on varsity letters, if desired.