Usual lifestyle tips:
* Remove all modifcations (if you can bear it. £500 is a lot to insure some £80 lowering springs)
* Be as accurate as possible with annual mileage (i.e. insurance companies figure the more you drive, the higher the chance of you needing to claim)
* Get a job (likewise those, even with a part time job, are deemed to be far more capable of paying an excess rather than not declaring accidents)
Usual insurance tips (things that you can easily change)
* Whack up the optional excess. Needless to say this is swings and roundabouts. The swing being cheaper yearly premiums. The roundabout being the £1000 excess on a £1500 car makes any crash a significant burden on your life. Paying huge excesses, hunting for new cars in a rush because you need to get to work, arguing over payouts etc really is not fun.
* Always go direct for a final price (comparison sites take a lot of commision)
* Pay in one lump sum rather than monthly (monthly payments include interest similar to a loan, so it ends up costing a few hundred £ more over the course of a year)
* Add your parents/older sister/grandmother (anyone who is stastically a lower insurance risk than you) etc as named drivers. This is completely legal if you are the #1 main driver with the policy in your name. It would not be legal for example if your dad insured the car on his policy with you as a named driver when, infact you are actually the named driver.
* "Market value" of your vehicle - play around with forms online and choose it carefully. E.g. insurance companies figure that, to an extent, you'll take more care driving a 4k car than a £500 car. Obviously you have to be reasonable, but I found my insurance was much cheaper when my 182 was worth £2999, as opposed to £3001. Insurance quotes are just a very long sum done by a computer so all these thresholds can make a big difference even if it seems illogical.
Needless to say never lie. Plenty of stories of people getting in very sticky circumstances when they crash and find their insurance is void (my favourite being the guy who tried to get cheaper insurance by saying the car was kept in a garage at his house, then when the insurance company visited his house, he doesn't even have a garage...)