I have a Select Electric hot water heater and the water does not stay hot enough to take a 10 minute shower. HOw do I turn up the temp?

I would bet that you've either burned out a heating element or the thermostat has gone bad.
Here (https://www.askmehelpdesk.com/plumbing/very-low-temp-out-hot-water-heater-306274.html) is a link to a really good, thorough explanation that walks you through step-by-step.

Hope this helps,
WallyH