Adjusting the shower mixer valve will allow you to regulate the water temperature of your shower. The shower mixer valve prevents the main water valve from turning to far to the hot water side. Water valves in new homes are often set to an unreasonably cool setting to prevent scalding and to save on hot water costs. Moving the shower mixer valve a few turns can give you the exact water temperature you are looking for.
Remove the hot water shower handle. You may need to remove a screw in order to do this.
Removing the handle will expose the hot water valve stem. There is a screw on the valve stem that prevents the water from moving too far to the hot side. Turn the screw a couple of turns counter clockwise.
Test the water temp by manually turning on the hot water valve.
Reattach the hot water handle and screw it back in place if necessary.