Over- or under-cooking the potatoes

This should go without saying, but one of the most common mistakes when making potato salad is over- or under-cooking the potatoes. It's simple, especially if you don't make potato salad on a regular basis and your potatoes are probably cooked to a different consistency most of the time. To begin, consider the type of potatoes you'll be working with. Waxy potatoes can be cooked for a longer period of time, but you should test them before draining them to ensure that they are thoroughly cooked. Starchy potatoes, on the other hand, will break down more easily, so keep an eye on the texture to ensure they don't become too soft during cooking.

The time it takes to boil a potato is largely determined by its size and type, with smaller potatoes cooking faster. If you're in a hurry, cutting your potatoes into small pieces will reduce cooking time but may increase the risk of overcooking. Undercooked potatoes will be too hard in your salad, and overcooked potatoes will turn into mashed potatoes (though mushy potatoes can sometimes make for great potato salad). Keep an eye on the potatoes as they cook so you know when to remove them — in this case, your best bet is to trust your potato salad-making instincts.