Remember, if you don't feel confident about carrying out any of these checks or if you just want a second opinion, both the AA and RAC (and probably your local garage) offer car checking services.

Most importantly, if you don't feel that the car is right for you, walk away. There are always plenty more cars for sale ...

Ensure the seller has the V5 vehicle registration document, and that the seller is the registered keeper. Check that the the VIN (vehicle identification number), engine number, colour and number plate match what's on the V5.

Check that the VIN plate in the engine bay has not been tampered with, and that any VIN numbers etched on glass match those on the V5. Any signs of forced entry, damaged or different locks suggest that they've been replaced, so look carefully round the car and try the key in all the locks. The same key should operate all the locks, and the central locking (including the remote control) should operate all the doors and the boot. If the car is equipped with an alarm, check it arms properly and can be activated by leaving a door or the bonnet open.

Make sure you have got all of the keys, and check the handbook to see which keys were provided when the car was new. Modern keys are expensive to replace and reprogramme, so ensure you have the coloured 'master' key or key code. Finally, ensure the sunroof and all the windows open and close properly.

The mileage should roughly tie in with the age and appearance of the car, using an average of 12,000 miles per year. Worn screws or scratch marks in the dashboard suggest that the instruments might have been tampered with, so look closely. Check that the mileage recorded on the service records, MOT certificates and other documents increase at a consistent rate year on year, and that it is consistent with the current mileage.

Inconsistent gaps between panels or mismatched colours on doors, bonnet and tailgate could indicate extensive repairs, so ensure you look out for an even paint finish across the car, and traces of spray paint on door handles, window seals and mouldings. Look under carpets and in the engine bay for signs that the car's colour might have been changed.

Check that the tyres (including the spare) are in good condition, and that there's no sign of excessive or uneven wear. Remember that tyres with less than 3mm of tread will have to be replaced soon, as the legal limit is 1.6mm. Ensure that all the seatbelts operate correctly, and there are no cuts or fraying that could affect the way they work. If airbags are fitted, check that warning lights operate as described in the handbook – normally they will come on with the ignition and then go out when the engine is started.

Check that there are no unusual noises when the engine is started from cold, the oil warning light goes out as soon as the engine starts, and that there are no signs of excessive visible exhaust emissions. Ensure the clutch is in good condition, there are no noises when you press down on the pedal, and that the biting point is smooth and progressive. For more advice on what to look for during the test drive, read the Car Hunter Test Drive Advice.

Check the underside of the oil filler cap for 'mayonnaise' as this could indicate poor servicing or a leaking head gasket. It is also worth checking the level of oil, coolant and water as this gives a good indication to how well maintained the car is. Too little oil shows neglect, and too much indicates that the engine is burning oil and has been recently over-filled to compensate.

Ensure the cambelt has been replaced according to the manufacturer's recommended intervals.

Once you are happy with the condition of the car, have been on a thorough test drive and have decided to buy the car, it is time to agree a price and leave a deposit. Print off and complete two copies of the Car Hunter Deposit Receipt (one for you and one for the buyer).

If you are paying cash, ask a friend to accompany you as a witness. Print off and complete two copies of the Car Hunter Receipt of Sale (one for you and one for the buyer), but remember that no wording on the receipt is foolproof. Ensure you and your buyer sign and date the receipts, and make sure you each keep a signed copy as proof of the purchase.

After the sale, it's important to tell the DVLA that the car has changed hands as soon as possible. Simply follow the instructions on the V5/registration document.