Being exposed to the environment is perhaps the easiest issue to deal with. All you need to do is wear the correct exposure suit for the water temperature you are diving in. You should base this on the temperature at depth which is usually a little colder than the surface.
Exposure to cold can be a limiting factor to our dive even with good exposure protection. If you feel yourself starting to shiver, your body is giving you a sign that it is getting cold and you need to consider finishing the dive and warming up.