Sauteed mushrooms are delicious in all sorts of dishes, whether you're eating them right out of the pan or adding them as an ingredient, but unless you want your mushrooms to become a wet, spongy mess when you cook them, make sure they're as dry as possible before tossing them in your pan.
Image from mdpettitt.
Bon Appetit explains a little wisdom that may be lost when you experiment with mushrooms in your dishes — drying them completely before cooking will minimise the amount of moisture they give up when they're heated. Mushrooms are already little sponges, in a way, so making sure they're completely dry will keep them from swimming in their own juice and getting rubbery and spongy instead of crisp, buttery and savoury.
Avoid salting the mushrooms before they're completely cooked, since that will also draw moisture out of the mushrooms and into the pan, again steaming them instead of letting them dry saute. The easiest way to avoid all of this is to wash them, then dry them with a towel and lay them out to air dry for a few hours before you cook them.