Is it safe for me to replace my electric water heater thermostat myself?
If you have to ask the answer is probably “NO”.
Um - could you be a bit more specific?
I have a 120V State Junior 10 gallon electric water heater (single element) under my kitchen cabinet that has started dispensing scalding water. I tried adjusting the thermostat, but it didn’t help.
Is it really that difficult to replace the thermostat? I am fairly handy. I guess I was hoping for tips or warnings about specific things I should look out for.
An installation guide would be super. 
It’s an easy job.
Turn off the power at the breaker.
Remove thermostat cover and plastic cover.
Check with a current tester to make certain you shut off the power at the breaker.
Compare new thermostat with old to be certain you have picked up the correct one.
Pull back the retaining tabs and slip the old thermostat out.
Take one wire off at a time and install it on the corresponding screw on the new unit.
Slip it back under the retainers, reinstall covers and turn the power back on.
If you don’t hear any frying sounds or see any smoke coming from the new unit pop a beer and bask in your new knowledge and self-confidence.