Controlling expense is a favorite of mine, from a business owners perspetive....
The very first thing you have to learn is the difference between the concepts of need and want. And all the recommendations I see to "get an app" make me laugh, especially where there is a statement saying it will save you x-amount and time too.
After that it is just a matter of reporting to some extent.
Utilities - don't pay a utility by using an account, use an item with qty and rate. Then reporting, hell even charting, will show you why utility expense is going up. If the rate is constant and elect is increasing - one of two things, something is wearing out and drawing more current, or there is mis-use somewhere.
Insurance, shop around every year - then call your present insurer and quote the lowest price for the same coverage, 99% of the time they will match it rather than increasing your premiem. And if they won't, cancel and start new coverage with a new insurance company.
IMO you should do the most to insure that fixed costs remain as close to fixed as possible.