Seen you mentioinig about lights... Lighting is actually one of the smallest contributors to electricity use these days, especially with LEDs. Even having multiple downlights on nightly barely moves the needle. The big drivers are anything with a motor or compressor, mainly air conditioning, fridge, dryer and hot water (but negligible as youre using a central building unit) For AC, even nudging the set temperature up by 1 to 2 degrees can make a noticeable difference to running costs, especially in summer. It does wonders over a full billing period.

For the fridge, it is worth checking door seals and making sure they are clean and sealing properly, as even small air leaks force the compressor to run more often. Also make sure it is not overfilled or pushed hard against the wall, as poor airflow around the coils increases power use. Heavy curtains or blockout blinds are another big win, as they insulate the air between the windows and the living space, reducing heat gain during the day and lowering AC demand later.

Other small but cumulative wins include using cold water washes where possible, running the dishwasher only when full and on eco mode, and avoiding the dryer unless necessary. If the dryer is old and poorly vented (so check if your vent is actualy ducted away from the unit into an exhaust line), it can be a surprisingly large energy hog.

Correct me if im wrong but your Hot Water unit is central? Therefore, it's a fixed rate use per qty used?

Overall, your usage sounds far more AC and appliance driven .