Horizontal lines are relaxing and easy-going. They will broaden and shorten the area they are covering. If you wish to look taller, avoid horizontal striped tops and square toe shoes, they won't help.
Vertical lines will make you appear taller, slimmer and are more powerful when used in suiting and business shirts. If you are carrying weight around your middle, wearing your jacket open can elongate and slim your torso.
Diagonal lines create interest and give your outfit an edge. Ideal diagonals should move from your right hip up to your left shoulder to look taller and more commanding. Diagonals that start near your chest or knees and finish with your hips will make you look wider.
Circular designs are friendly and welcoming. They can soften your image and enlarge the area they are covering.