Give up tea and coffee
If you have a launderette nearby use their dryers, they're often big and cheap
Get an electric blanket and/or throw
Battery or rechargeable sensor or touch lights - had these in the understairs cupboard, bathroom and under kitchen units for years. Rechargeable Fatboy lights too
Walk
Pick blackberries, they're everywhere.
Plant things that don't need much water - lavender, geraniums, hebe etc
I charge my phone at work, I use my phone for work, no one will convince me this is stealing. I also charge it on the train. Until they take away the toaster I will also continue to make my breakfast at work.
Only ever have one netflix/amazon/now/apple etc subscription on the go - sign up again when there's plenty of stuff to blast through watching in a month, then cancel again for a while.
This winter, on days off, we will mainly be found in free museums and art galleries, culture will keep us warm, yes it will, it's that or sitting on the circle line all day.