How to score auto insurance discounts

Recently I went shopping for auto insurance. I entered my zip code above (wink wink) and then got prices from various insurers. You'll get multiple quotes while making my sponsors happy! "Winning."

Back to me, I ended up staying with my current insurer since the other agents could not touch the price. Most other companies I looked at all were within $200 of each other initially. But that's where the similarities ended. Every auto insurer underwrites risk slightly differently. Just as there are different discounts, there are different ways to get those discounts. Some are not even labeled discounts, like paying your premiums annually (no finance charge).

Other ways to save some mulough on your car insurance:

Multiple vehicle self explanatory, around 20%.
Let your car insurer know you are married, some even credit for domestic partnerships.
Let the insurer know you are retired military (Unless you are with USAA who will already know!)
Combine your auto and homeowners through the same carrier (Works great for the higher priced big name carriers who already overcharge).
Senior discount unless you are way old (Over 75) and frighten your relatives (and the insurer), and they are looking for an excuse to take away your independence.
Lower mileage adjustment only if reduced our driving from one year to the next beyond the insurance company's breakpoints. For example, they are not going to credit you if you drive 100 miles less, unless its the dif between 4900 miles and 5000 miles in a year. Combine trips and carpool, if you can stand it. Also it's good for the environment. Why does everyone mention that as an afterthought?
Safe driver discounts, but this is not for new customers. You ahve to be with the carrier for at least 3 years, no (at fault) accidents and not more than 1 1 point ticket. California mandates it, so the insurer is not doing you a favor.
Improving your credit score. There are strange happenings when your finances and credit score go south. Everyone wants to charge you more for stuff. Insurers can't use insurance / credit score in California, but in state's where it's allowed, you will end up paying either higher finance charges, higher premiums or both. Pay your bills on time. More of a rarity these days.
Good student discount. Work a B or higher and many insurers will give you a 5-10% discount. Better than a stick in the eye!
Teacher discount depending on the carrier and you will most likely need to be state certified or otherwise credentialed. At least join the NEA.
Safety equipment. Car insurers love um because injury claims can get insane. Seat belts, Air bags, alarms, most of that stuff is standard equipment now anyway. But if your agent does not ask for it volunteer the info so they know. The online form you fill out (hint hint) to help me support the site should ask about safety equipment.
Hybrid vehicles did often qualify for a discount depending on the insurer.

Well my copyrighter tells me this page is too long already and you'll never read it. I love to prove that guy wrong! Email me and tell me about some other arcane discount I forgot to mention, like farm vehicles used exclusively on on a ranch.