I grew up in an area where culturally it was the norm to be frugal so I'm lucky that a lot of these habits are just normal to me.
I make coffee and lunch at home, we don't really buy ready meals or packaged snacks like chocolate, cakes, sweets, crisps, juices, etc. Things like jarred sauces, condiments and dips can add up as well. I don't drink at home so never buy alcohol and we don't eat many meat heavy dishes. We stopped ordering takeaway when we realised how much we were wasting on fees. We've made an agreement that we have to go out so at least we get a nice experience if we're spending money. If it's simply an issue of being lazy and we can't be bothered to go out we will cook. Learning to cook things from scratch was probably the biggest money saver for me.
We live in a city so don't have a car or any associated costs. My style is pretty classic so I don't buy many clothes or follow trends. I try to shop intentionally by thinking about what I'm missing from my wardrobe (good winter coat, long sleeve tops) and buying quality items, preferably on sale. I don't really browse and buy things impulsively. Things that are well made like boots will be repaired rather than replaced.
I do get my hair done now that I'm going grey, but I've never been in the habit of getting manicures or regular beauty treatments. However I do cut open all of my products to get every last drop!
We try to dress warmly and address any draughts before turning on the heat and keep it at around 18 degrees. I lived in a dorm when I was at uni and remember facilities saying they didn't turn the heat on until the external temp went under 40F (so about 5C) and I try to keep that in my mind.