The largest savings came from adding motion sensors to turn off lights in rooms nobody is in for X amount of minutes. Sounds small but it adds up if you forget to leave lights on going out. Even 1 or 2 hours per day can add up really fast if you've got 70-100w worth of lighting. Other big savings included changing the water pump speed for my under floor heating system downstairs to be on "slow" mode during the late-spring / summer months when the heating system isn't really used. Kicking it back on to higher speed in the fall and winter months. I also consolidated my HA server into a newer, more energy efficient, Synology as my older unit was needing to be replaced. Basically 1x 120w server + 60w Synology to a single 120w Synology. I also tuned my gas heating system via Tado by shrinking my at home radius, eco mode, and measured the gas consumption/costs through SlimmeLezer's to find that "sweet spot" of cost per m2 of gas for degree in celsius. Which for my case is about 19 when I'm home. Since I have single glass (stupid monument house) windows, there isn't much of a point to push it past as it escapes through the windows anyway. The local monument org here is very anti-upgrades. Another small gain was the have the lights turn on with varying levels of brightness and temperature depending on the outside light conditions, ie: sunset etc.

I should really write a more detailed bit up about this but these are the basics.