Summarize:

The most obvious way to make your legs seem longer is to wear shoes that add inches to your height. High heels will also force your feet to extend, which makes your calves look longer and more shapely. Avoid wearing heels too often. Over time, high heels can damage your joints and cause chronic back pain. A shoe that blends in with your skin will create a long, uninterrupted line when you're wearing skirts or shorts. Both the solid color and added length from your feet will create the illusion of longer legs. You can also create that same uninterrupted line by coordinating your shoes when wearing tights or pants. For example, try wearing black hosiery with black heels. This monochromatic look creates a clean line as the eye travels from the top of your leg straight down to the floor without stopping. The horizontal straps cause the viewer's eye to pause early, making your legs look shorter. Ankle straps have the opposite effect of high heels and v-shaped cuts. If you love ankle straps, consider wearing tights in the same color as the strap to prevent the line of your legs from being broken up. Over-the-knee boots create a clean, uninterrupted look from your lower thigh down to the floor. Knee high boots have a similar but less exaggerated effect. Ankle boots, on the other hand, cut your leg off just above the foot. Like ankle straps, they make your legs look shorter than they are. An ankle boot with a v-cut at its top instead of a horizontal line is exempt from this rule. A pointed v-cut ankle boot can even make your legs look longer in its own right, as they extend the line of your legs downwards. A pointed toe will extend your feet (and your legs) twofold: First, shoes with pointed toes typically have at least an inch or two of extra space making them physically longer than a round-toe shoe in the same size. Second, the tapering point also creates the illusion that your feet (and consequently legs) are even longer.
Add more high heels and platforms to your wardrobe. Wear shoes that are close to your skin tone. Match your shoes with your pants or stockings. Avoid ankle straps. Wear long boots. Go for a pointed toe.