Scott, first try raising the temperature setting on the water heater. How big is it? If that doesnt work, either turn your water down, take shorter showers, or install a water saving shower head that will force less consumption. Is it an electric heater? If so, might be that one of the two elements is out, which impacts significantly on the recovery time (especially if its the bottom element out). You can check to see if an elements bad by disconnecting the power supply from it, and checking continuity/resistance with a meter – if theres no continuity (resistance at infinity) the elements bad.