Step 1: Layout
Lay the jacket out on a flat surface and zip it up.
Step 2: Folding the Sleeves
Take one sleeve and fold it over the chest. The end of the sleeve should touch the seam where the opposite sleeve begins*. Repeat process with other sleeve.
*for a bigger jacket (where the sleeves will be too long to match the wrist to the opposite shoulder seam) simply fold to the seam and then down at a ninety degree angle.
Step 3: Bring the Shoulders In
Grab the outside edges of the jacket and fold them in so that they touch in the middle.
Step 4: Roll
Tightly roll the bottom of the jacket up toward the collar.
Step 5: Success
Tuck your rolled jacket body into the hood and you're done. If the jacket in question doesn't have a hood may use a rubber band or tie the rolled jacket with ribbon.