Warning: Car insurance up 20% and more to come. Check NOW if you can LOCK IN cheap

Here's a tweet I got from @iainthorley:

"Just saved £375 changing car insurance MID-POLICY thanks to - thank you, man."

So not only is he saving straightaway, he's locked the price in for the next year, forestalling any rises. Below are my need-to-knows, for full help see the Cheap Car Insurance & Young Drivers' Insurance guides. If you have any car insurance questions you can tweet the MSE team this Thu, 1pm to 1.30pm.

1. Ensure you're on TODAY'S cheapest deal, then if prices rise you're protected. If the predictions are correct and prices keep moving up, today's prices will soon look cheap. Plus many are overpaying already, especially those who just auto-renewed. Here's what to do... - AT RENEWAL: Then it's easy, just move on to point two. - RENEWAL WITHIN 60 DAYS? Some firms such as Aviva*, Nationwide & LV* give quotes valid for 60 days (see full list of 20 long-quote insurers) so get one now, then check against quotes at renewal time. As @dimuthuj7 tweeted: "@MartinSLewis. Renewal £521. Quote a month ago, which was honoured, of £319. Thanks." - MIDWAY THROUGH A POLICY: Follow the steps below to see if you can save a chunk by switching. If so, provided you've not claimed, for a £50ish admin fee (factor that in) you can usually cancel and get the rest of the year refunded. You won't earn the year's no-claims bonus though, but if it means you save now and prevent future price rises it can be a big winner. Full help in Switching mid-policy.

2. Don't just use one comparison site, combine them. There's no one cheapest insurer, as prices are set individually. So the aim's to check as many quotes as possible, quickly and easily. Comparison sites do that, yet they don't all cover the same insurers or even give the same price for the same insurer, so use more than one. Our current order's Confused.com*, Gocompare* & Moneysup* (see how we rank them), if you can use all three. Speed tip. Open the sites in a few tabs, then fill them in together by copying & pasting info. To copy, highlight the text and press CTRL 'C'; to paste press CTRL 'V' (on Macs replace CTRL with CMD).

3. Then check the biggies comparison sites miss.Direct Line*, Aviva* & Zurich won't appear on comparison sites, and can be competitive especially if you've no convictions and a clean licence. As @damianderby tweeted me: "Did your car insurance checklist and saved £100 (1/3) off my renewal. It was Aviva. Pays 2 go past the comparison sites.

4. Hidden hot deals comparison sites miss... eg, £60 Amazon vch. There are also special promo deals around, some of which aren't listed on comparison sites, others are blagged by MSE. So we collate them in our Hot car insurance deals section. Current highlights for switchers include...

- £60 voucher for Amazon, HofF, Debhms, Ticketmaster. Use this Churchill* link to get a policy by Mon 9 May and after 100 days you're emailed to select a £60 vch (so check your spam file). See Churchill deal info.- £55 Amazon voucher: If you get a policy via this Age UK* link by 31 May, it will be sent within 120 days. - Fitbit Flex with multi-car: If you get an Admiral MultiCar* policy via this link by Tue 31 May. It will be sent within 30 days. Once you know your cheapest, check if a cashback site will pay you to buy through it. See Car cashback.

5. Check multi-car policies if you've more than one car in the home. A few insurers offer special discounts if you have more than one car. It's always worth trial & error to compare these against standalone deals. Sadly comparison sites' tech doesn't allow this, so do it manually. Admiral MultiCar* gives discounts of up to 25% depending on how many cars you insure and currently this link gets you a Fitbit Flex with a policy too (see above). You can also get discounts by linking the household standalone policies with Churchill*, Direct Line* & Privilege*. When it does win, it can win large, as forumite foolsgold01 found: "We were paying £876/yr jointly for our insurance. We checked the multi-car policy deal and saved £449 a year."

6. Don't always use your common sense... comprehensive can undercut 3rd party and insuring more people can cost less. It's all about risk averages and 'actuarial' tables. That can lead to bizarre ways to save. - Comprehensive may be cheaper than third party. Merely selecting comprehensive means some insurers see you as a lower risk. So if you want the cheapest cover, check if comprehensive's cheaper? - Adding extra drivers can cut your cost. If they're a lower risk than you, it sometimes brings the average down. This is especially strong if you're a young driver adding a responsible older driver, yet everyone should try, as forumite Bouncybubbles told us: "Quoted £900 from £500 previous year. By comparing then adding my husband I got it down to £298." For the rules see Adding a responsible older driver.

Warning: Car insurance up 20% and more to come. Check NOW if you can LOCK IN cheap

7. Legitimately tweak your job title. You can't claim to be the boss of Barclays if you're a 'butler in the buff' (or vice-versa). Yet I once did a TV makeover for someone who saved £50ish by calling himself "bar staff", not "bar steward". Fabsternation tweeted: "Changed from creative director to marketing manager - saved £300+".

Our fun Job Picker tool (it's old, we plan to update it soon) may help.

8. 'Paying monthly' doesn't exist - instead it's a 107% APR loan. Insurers may call it paying monthly, but actually they loan you the year's cost and charge often hideous interest. Kwik Fit Insurance is the worst offender we've found, with a disgraceful 107.4% APR. So pay upfront if you can as many insurers charge over 20% (check your insurer's APR) - that's more than a typical credit card. If needed, get one of the many year-long-plus 0% credit cards. Just ensure you pay it off over the year, then there's no cost (see 0% Cards Eligibility Calc to see whether you'll be accepted).

9. Don't want to switch insurer? Haggle, haggle, haggle. This works best at renewal. Simply find the best price you can at speed and then ask your existing provider to beat or match it. Often it will. Eddy emailed: <"My car insurance renewal offer arrived, a shocking £345. A quick phone call achieved a reduction to £143 - not bad."PS: Don't be surprised if your existing insurer offers a far cheaper price as a new customer via comparisons than its renewal quote.

10. Cover still too costly? Consider a 'black box'. This device (officially called 'telematics') is the tech insurers put inside your car to monitor your actions behind the wheel, and when and how much you drive. They're especially useful for younger drivers facing hefty premiums, though if your mileage is limited they can work well too. Forumite vic.star used one to save £100s: "Via telematics I paid £980 in my first year, vs comparison sites' cheapest of £1,400."For example, Coverbox* gives you prices based on set mile limits. With Co-op*and Direct Line Drive Plus*, you can earn 22.5% and 25% discounts respectively. More info in Cheap telematics policies.

This article first appeared in the MoneySavingExpert.com weekly email on 2 November.

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