Simple clothing choices are best for creating timeless portraits. I suggest mostly solid colors, avoiding too many busy patterns and logo/wording that tend to draw attention away from the face. Jeans, dresses and khakis are classics and photograph well. Add in some texture and layers and you can't go wrong. Don't forget to accessorize; hats, scarves, belts and shoes, can all add fun and personality to your photos. You should coordinate your style and colors, but not all matching. Start with one outfit and build from there. Keep it simple.