One of the most common mistakes made with moisturizers is overuse. Always use moisturizers in moderation. The amount you use is not the key to getting your skin nice and hydrated; instead focus on the type of moisturizer and the thickness of the product.
For example, dry skin types should use thick, creamy moisturizers; oily skin types should try a lightweight product; those with problem areas everywhere should use an all-over, body moisturizer. Do not slather on the moisturizer; instead, spread it around in a thin film and work it into the skin for optimal results.