Fitting an approved immobiliser or an alarm (if your car doesn’t already have one installed) or consistently using a steering lock reduce the chances of your vehicle being stolen and therefore your ‘risk’ will be decreased and your premiums also. Keeping your vehicle in a secure garage could also reduce your premiums. Glass etching (etching the registration number) can also be a further deterrent to thieves. Check with your insurer to see which makes/models of immobiliser/alarm are on their approved list to reduce your premium.
Don’t forget to remove high value items from your car when you leave it. If you have a car stereo, invest in one where you can remove the face of the radio. Don’t leave your Sat Nav, iPods or other devices visible in the car!