One of the simplest ways to do this is to keep your shoes in the shoe box you purchased them in. Not only does it keep your shoes organized and keep them looking like they're new, they keep the light from shining on them. This is important because the lighting from your closet can make the color on your shoes fade. A better way to do this is to store your shoes in cotton or felt shoe bags so they can breathe even though they are covered. If you're one of those people who enjoy seeing their shoes in their closet, at least put them in a clear box with an opaque top so they are away from lighting in some way.
A quick way to prevent permanent damage to your shoes is to buy that water protector that boutiques offer you when you buy your shoes, it's usually no more than $5. Don't blow dry your shoes after you spray. This can cause them to shrink. If your shoes get stained, treat them immediately. If your suede shoes get water spots, buff them with a suede stone or brush. If your leather boots get salt stains, it's best to wipe them down with a damp cloth as soon as possible. You can remove scuffs on your patent leather shoes with nail polish remover but I don't suggest applying too much as this can wear out the color and appearance of your shoes overtime.
Your shoes can even get worn out just by sitting in your closet even though you aren't wearing them. Make sure your closet is room temperature, if it's too hot those leather shoes will shrink. If your shoes are wet inside a box, they will cause odor, bacteria and mold. Ew! It's also important to keep your shoes an equal distance a part if you aren't covering them. Your patent leather and leather shoes could actually bleed (rub off) on each other!
FASHION TIP: Store your shoes away from your clothes in your closet to prevent the odor of your shoes to get into your clothes.