Lay the top of your suit jacket into your suitcase. The bottom portion of the jacket should hang out from the bottom of the suitcase.
Fold the jacket's sleeves diagonally across its back so the wrists meet near the bottom of the jacket.
Lay your business pants into the suitcase in a similar manner, with the ends of the pants hanging out of the suitcase. You may leave them pointing downward like the jacket, or, if you prefer, pointing out the sides of the suitcase.
Pack everything else you intend to bring into the suitcase. Leave the ends of the jacket and pants hanging out of the suitcase as you do this.
Fold the jacket and pants up over the other items you packed in your suitcase.
Close the suitcase, being careful not to wrinkle or crease the suit as you do so.