Batch cook
Meal plan
Shop yellow stickers and utilise your freezer
Track your bills, is there anything you can cancel? Spotify, Apple Music, Netflix, tv package, phone contract and move to sim only, fix onto a mortgage deal with a lower interest, can you get a cheaper broadband deal? Etc.
Track your spending, we have a separate account for spending which we transfer money into every week.
Reduce the temperature on your thermostat and your boiler
Turn radiators off in rooms you're not using
Submit regular meter readings so your bill is accurate
Put water bottles in your toilet cistern to use less water if on a water meter
Keep water in a flask instead of keep boiling the kettle
I could go on all day 
Oh last one.. always google promotion codes before ordering anything, even before booking mots etc