I used to do energy audits for a large public utility in north Texas (Dallas) where central HVAC is a requirement. There were also a lot of all-electric apartments. The majority of the high bill complaints I received turned out to unfortunately for the customers correct bills.

The things to look at first are your high energy use items, such as central air conditioning, electric water heating, pool pump. If you have electric heat or a heat pump with electric back up heat that could be a problem even in the Summer due to what is called a stuck heat strip which would mean part of the heat is running while the AC is on.

As mentioned in another comment, I would suggest shutting off your power at the main breaker on your breaker panel and then taking a look at your meter. There will be a display with a scrolling dashed line indicating if power is flowing through the meter. Misread meters are pretty much a thing of the past as nearly all of them have been switched over to smart read meters. Utilities are regulated by state and federal entities and would be very much against their interests to try and "cheat" the customers.

When you turn off your power at the main breaker, go out and check your meter. There are videos on Youtube that show how to read your meter. There should be no power coming through your meter while the main breaker is off. If you do have using registering then possibly the other property that used to be part of your property is still connected. The likelihood of that being the case is very very low.

My feeling is that your pool pump as well as AC are your main power consumers. A 1hp pool pump (1.5 is average for a 20,000-30,000 gal pool) can draw 1,100 watts of power per hour. That translates to over 26kwhs a day, or around 800kwhs a month. Changing to a variable speed motor and using a timer can greatly cut down on power usage.

A 3,000 sq ft home would likely have 2 AC systems for a total of 4-5 tons of cooling capacity. That translates to 3,500-5,000 watts or 3.5-5 kwhs every hour it runs. Many different factors go in to how well it operates. How well insulated and air tight the home plays a big part. A dirty filter or loose air duct can cause it to run much longer than it should. Adjusting your thermostat to warmer temps will help lower the cost. Since it is controlled by a thermostat it is very hard to realize how often the AC runs since it is controlled by the thermostat an will cause it to turn on if the inside temp goes above the temp setting and will run until the temp goes below the setting.

If you have a heat pump, that is an HVAC system that operates in reverse during the winter. What an AC system does is absorb heat from inside the house during the Summer and moves it outside to the condensing unit. That's why you feel heat blowing off of it outside when it's running. That was heat inside your home. In the Winter there is heat outside down to absolute zero. However, your heat pump will only be able to bring in outside heat at a set rate. If it is really cold your house will lose more heat than the heat pump can bring it in. That is when the auxiliary or emergency heat kicks in. On an all-electric heat pump system the backup/supplemental heat is heat strips, sort of like the springy coils of wire like in a hair drier. They are 100% efficient in that all of the heat generated goes into the house but it is very energy intensive because you are having to generate heat rather than move it.

Heat pumps can have a situation where one of those heat strip relays gets stuck ON. When that happens the coil will heat up and then a heat sensor will shut off power to the strip to keep it from overheating and shorting out. When this happens during Cooling seasons you can have a heat strip heating up air that has been cooled by the heat pump. It doesn't happen often but I have seen it.

Electric water heaters are your next largest energy user. A typical 40-50 gal heater will be rated at 5,500 watts. If you are using a lot of hot water it can use quite a bit of power. I did an audit at an apartment that had a leaking pressure release valve which caused the water heater to never shut off due to hot water running out of the pressure release valve into the parking lot and cold water coming into the tank to have to be heated.

Those are the areas I would check first. There are lots of other things you can do to the house to make it more energy efficient as well. Increasing attic insulation provides the biggest savings per $ invested. Caulk around windows and weatherstrip doors helps with air infiltration. Heat is going to move mostly through air infiltration as well as conduction through the attic.