Hang your suit on the garment hook in the backseat of your car, if you're traveling by automobile.
Get some high quality garment bags if you will travel by plane or bus. Garment bags are good for keeping your suit wrinkle free. Many airlines have a closet for business travelers to hang suits during the flight. However, garment bags aren't convenient for long or multipurpose trips. If you're going to be dressing in casual wear for part of a short trip, buy the largest carry-on luggage you can find, to give your suit as much room as possible. If you're going to be taking an extended vacation, put your suit in your largest checked bag.
Fold your suit properly if hanging it in a garment bag isn't an option. Crease your suit pants so that the inseams are touching. Fold them lengthwise over a plastic hanger, and hang your suit jacket over your pants, leaving it unbuttoned. Fold the arms of the jacket toward each other in a v-shape. Wrap the suit carefully in cleaners plastic.
Fold the suit in half, bringing the pants toward the collar. Fold the suit around a towel or extra shirts, so you don't make a deep crease. Don't put your suit directly on the top or bottom of your bag; keep your suit cushioned between other clothing so it doesn't get damaged in transit.
Hang up your suit as soon as you arrive at your destination. Remove it from the plastic cleaners bag, and hang the jacket and pants up separately so the wrinkles will fall out. If you need help getting the wrinkles out, hang suit in the bathroom run the shower on hot until steam forms. Many hotels offer cleaning and pressing services; have the wrinkles professionally removed from your suit if you have the time.
