A few things I guess..
Hate waste so will only cook/use the correct amount of food needed for that meal.
Never go by best before dates, apart from maybe chicken. You can tell if it is off/mouldy.
Buy all meat/fish on quick sale and freeze unless we fancy something on a whim, say Steak.
Buy toiletries 3 for 2. Have a stock of face cream, hair dye, hand cream, shampoo etc for about a year 
Cut my own and Dh's hair (did train as a hairdresser). Ds hasn't needed a hair cut as yet. Also dye my own hair, that alone must save me hundreds a year!
Buy own brands for things like hand wash, washing powder, fabric conditioner etc and always use less than recommended.
Try to have heating on as less as possible during the day, as soon as it is warm turn it off.
Switch all plugs off after use
Save wrapping paper/bags
The list goes on.. 
Writing all this down I didn't realise how much I was doing to save money..