Pack light. Smashing too many clothes into your suitcase causes wrinkles. The pressure of the clothes on top of each other forms wrinkles in the creases.
Purchase clothing in wrinkle resistant fabrics. Knits, wrinkle free cottons and other permanent press fabrics are best for traveling, while linen, silks and other cottons are not. In recent years, clothing companies have developed many different types of wrinkle resistant fabrics that are practical as well as fashionable.
Use plastic or tissue paper between your clothing items. When you pack your garment bag, place each of your hanger items in a plastic dry cleaner bags. The slippery bags cause less friction and thus less wrinkling. The same concept applies to your suitcase; place tissue paper between each of your folded items in your suitcase.
Roll jeans and t-shirts. Rolling your clothes not only saves space, but also reduces wrinkling because the items are not pressed together as much. Fold jeans and t-shirts in half length wise and then roll them from the bottom.
Place heavy items at the bottom of your luggage. Your toiletry bag (or a plastic bag holding toiletry items) and shoes should be put in the bottom of your suitcase, if your suitcase were stood up. Heavy items weighing on clothing can cause many wrinkles.
After packing all your items in your suitcase, check for big gaps. If you have several gaps, fill them in with socks and rolled items. If there are too many gaps, your clothing will shift during travel and wrinkle.