Yes, there are more. In addition to being rewarded for your high credit score, your social life, your profession, and your commitment to paperless billing, here are a few more factors which, if they apply to you, ought to be able to help lower your insurance rates:
Driving a hybrid car. It isn't that hybrid cars are safer than their gas guzzling counterparts. However, the statistics that insurance providers rely on repeatedly show that drivers of hybrid cars tend to be involved in less collisions than the average rates. The hypothesis here is roughly that people who care about conserving resources (and managing their finances well by diminishing the amounts of money they spend on fuel) are committed to doing most things right: they share the road considerately, and do their best to avoid dangerous situations. So if you drive a hybrid car, be sure to mention this to your insurance provider!
Safety features of your vehicle. Airbags and anti skid lock brakes are the most commonly known and implemented safety features found in cars being manufactured today. Obviously the more safety devices your vehicle has, the less chances there are of collision, and the less the extent of damage if there is a collision.
Theft deterrents. Your vehicle is likely equipped with basic anti-theft mechanisms, such as a motion activated alarm. However, there are measures you can take to make theft even less likely, and doing so is doubly beneficial to you: you lower the chances of your car being stolen, and you lower your insurance premiums. There are several means by which to do this: there are switches that will disable fuel and ignition when improperly activated. There are also systems for tracking stolen vehicles. Additionally, engraving your vehicle's identification number on various parts of your car make it easier to identify and retrieve it if it is stolen.
Your loyalty. Have you been with the same insurance provider for a long time? Or are you using the same provider for all of your insurance needs, home, auto, and so forth? Ask them to make it worth your while! Chances are that they will only be too happy to use this means of thanking a valued customer.
Good grades. If you are a student, having good grades does the same for you that having high credit scores does for your parents. Good grades (usually) go hand in hand with responsibility, and statistics do show that this responsibility is carried out onto the roads.