From this article on my site:
Water Content of Meat and Poultry
The amount of naturally occurring water, or moisture, present in meat and poultry may surprise consumers. An eye of round roast is 73% water before cooking. The same roast after roasting contains 65% water. A whole broiler-fryer contains 66% water before cooking and 60% afterwards. Leaner meat and poultry contain more protein and less fat. Since water is a component of protein (but not fat), a leaner cut will contain slightly more water on a per weight basis.
Chicken is listed at 66-69% raw and 59-61% cooked.
So with all that in mind, how do you go about cooking a nice brown crispy on the outside and tender and succulent on the inside piece of chicken without accidentally boiling it in it's own juices.
First, as was stated in the other answer, consider the type of pan that you are using, a wide shallow sided skillet is great, however, depending upon what you are then going to do with the product, and how much washing up you want to do, then a large based pan will also do. Consider the type of oil/fat that you are using, and the temperature at which you are cooking.
A good quality olive oil is a must for most dishes. Put your pan on a nearly high setting, too high and you will burn not only your product but also change the nature of the oil that you are using. Pat your product dry with kitchen towel then place in the pan. Resist the temptation to flatten the item or turn too quickly, food does not like to be beaten up, be gentle with it. You may need to to 'unstick' your item from the bottom of the pan, if so, also turn your pan down a touch. After a couple of mins, turn the item over. That should do the trick.