Low(er) flow faucet aerators & shower heads (don’t have to get crazy but try a few at different flows to see if you can go any lower without it being obnoxious, I stopped at 1.5gpm as the 1gpm restrictors felt like a stingy public bathroom)
Adjust water heater to a cooler temp (at 125-130F I can still get the shower as hot as I need just by turning it close to full hot)
LEDs in all light fixtures, I usually calculate lumens per watt to get the most efficient I can find while still having ~80+ cri and a 2700-3000k temperature (colder temperatures are usually more efficient but I’m not about living in blue light)
IR reflecting window film for the summer and draft-reducing film for the winter
Weather stripping to fill any drafty gaps
Make sure HVAC filter is changed on time and not restricting air flow
Simply let it get a bit warm in the summer and a bit chilly in the winter, use eco modes if your thermostat has it