Make sure you open your curtains in the day, and close them when it gets dark.
Letting sunlight in during the day makes use of free heat.
Closing your curtains when it gets dark acts as a layer of insulation.
Use timers on your central heating
Programming your boiler to turn the heating on a little earlier at a lower temperature is cheaper than turning it on when you need it at a higher temperature.
Don't leave your heating on low all day if you're out. You're paying for heat when you don't need it. Set it to come on just as you are due to get home. If you're only going to be out for a couple of hours, turn your thermostat down.