For the love of all that is holy, do not overcook your chicken. Here are some tips to achieve the perfect undercooked state:
Don't just rely on the color of the chicken, use a thermometer to get an accurate reading. 165°F is the key, folks.
Stop pressing on the chicken, you'll just push all the juices out and make it dry and flavorless. Let it cook in peace.
Don't overcrowd your pan, cook in batches if you must. You don't want to steam the chicken instead of searing it.
Let the chicken rest, don't slice into it immediately. You'll just be a hero with a plate of dry, flavorless chicken.