If you have not already get a room thermostat fitted, average saving according to Energy Saving Trust £70 a year.
Thermostatic radiator valves, use these to limit heat room by room.
Reduce your property heat loss with loft insulation, cavity wall insulation, double glazing and if possible insulation under the ground floor this is a major source of heat loss. (Ground floors; if you have drafts coming through floor boards you can fill in the gaps with sealant, or find a coloured mastic to suit your floors.)
Turn down the heating setting on your boiler, it doesn't need to be at maximum other than in the coldest periods of winter.
Turn down your hot water setting; if your always blending your hot water as it's too hot on it's own your wasting energy. On cylinders turn down your cylinder stat, on combination boilers you can turn down the hot water setting.
Hot water return pumps; if you have a hot water return circuit, turn it off over night or when everyone's at work and school. This circuit can be cooling down your cylinder especially if the pipes are not very well lagged.
Any accessible heating or hot water pipes can be covered with inexpensive foam lagging, cheap and easy DIY.
Turn of comfort settings on boilers, most home owners and tenants don't even know these exist.
Read or download your boiler manuals so you can learn how to use them to there maximum efficiency.
Keep your pipes clear on the inside; Fit scale inhibitors on hot water systems (not necessary if you have a water softener) and fit magnetic filters on your heating circuits, Magna Clean estimate a 6% saving on heating bills by fitting there products.
For more information I recommend Energy Saving Trusts Website