buying 2nd hand cars is both technical and emotional. I think the other posters discussed the technical side pretty well. So umpisahan mo sa papeles, then sa technicalities nung car.
Sa case ko na walang access sa mekaniko (at wala din akong alam gaano sa kotse), I look for service records. Pag walang service record, walk-away na. Sa experience ko kasi, yung mga responsible 1st owners always maintain a file of service history, and these are handed over to the 2nd owner. So kung walang service records, eh malamang may itinatago about the car.
You have to handle your emotions, lalu na kapag nakakita ka ng kotse na makinis, makintab at mabango sa loob. Hwag kang magmadali...Take your time to check the car, compare it with your other prospects. Never rush in to a sale....unless kilala mo yung may-ari.
Alamin mo din yung price range ng specific models...para alam ko kung hanggang saan ka tatawad.
Use the car dealership for benchmarks...para may reference ka. Pero they should be your last option...sabi nga nung isang poster. Try to get cars from 1st owners.
Hope this helps. Happy hunting. enjoy the experience.