To apply sunscreen, start with a generous amount, typically about a nickel-sized dollop for your face and a shot glass full for your body. Apply it evenly to all exposed skin, including areas often missed like the ears, back of the neck, and tops of the feet. Reapply sunscreen every two hours, or more often if swimming or sweating. It's essential to use a broad-spectrum product with an SPF of at least 30 for effective protection against both UVA and UVB rays. Always check the expiration date to ensure the product is still effective.