What energy saving methods can I use for a new gas water heater?
A blanket is unnecessary and some manufacturers of tank WHs state that a blanket should not be added.

The temperature set point of a tank should not be below 130 F and some say not below 140 F. This high temperature is necessary to prevent the growth of Legionella bacteria. For the same reason a timer is not recommended and I don't think a gas tank can be controlled by a timer.

Research the proper temperature setting and just use the heater as it is equipped. If you have a shower with a thermostatic anti-scald valve it would be OK to use 140 F, but if you don't, then you might want to use the lowest recommended temperature setting. A lot depends on how many people in your house want to shower at the same time or in quick succession.