Add 2nd (and even 3rd) named drivers with no convictions/accidents and plenty of experience. Drops my premium by £100.
Tweak your job, the difference between "Web Designer", "Managing director" and "Network controller" - under which I fall under all 3, is a £130 difference.
Removing the all-too-popular £20k personal injury cover.
Reducing mileage to that of your previous years MOT to this. I only do 4k per year, so it knocks down my premium.
Fit a Thatcham recognised alarm/immobiliser.
Pass-plus
Reduce number of mods on the car
Fully comp. is usually cheaper than 3rd party for me.
Lower declared vehicle value to something more inline with that of the current market.
Park on a driveway, in a garage, in a car port.