There are a huge number of things you can do to your home to cut your energy bills and reduce your carbon footprint, from free and low-cost improvements though to larger and more costly changes.
If you are thinking about making changes, we recommend that you:
Do some research. Visit a home which has already made the improvement(s) you're interested in, read up about your options, think about the costs and practicalities (e.g. can you do it yourself, or is it a job for a professional?).
Get quotes. At least two, but more if possible. This way you can be reasonably sure you're getting value for money.
Seek recommendations and accreditation. Whether it's a service or a product, find out whether there is industry accreditation. You might also ask about feedback from other customers.
If you want more information on anything from solid wall insulation to solar PV, and from DIY draught-proofing to central heating controls, a good first port of call is the Home Energy Advice part of the Centre for Sustainable Energy's website.