To properly tuck in your shirt, start by buttoning up your shirt and putting on your pants as you normally would. Then, tuck the bottom of your shirt into the waistband and use your thumbs to smooth out any wrinkles by running them from the front to the sides of the waistband. For a more fitted appearance, pinch the fabric of the shirt on each side and fold it back on itself. Finally, ensure that the placket of your shirt lines up with the zipper of your pants to create a clean and professional look.