Turn the suit jacket inside out
Fold one shoulder back into the other shoulder
Lay the jacket flat with the sleeves aligned
Fold the jacket in half vertically
Fold the jacket horizontally if needed to fit your bag
Place tissue paper or a dry-cleaning bag between folds if available
Fold the trousers along the crease
Fold the trousers in half or thirds depending on suitcase size
Place the folded jacket on top of the trousers
Put the suit in the suitcase with minimal compression
Unpack and hang the suit as soon as possible