I have learned a lot over the years through buying, selling and parting out used vehicles. This video is an explanation of things I check for when looking at a used car.
When checking out a used car you should already be familiar with the vehicle and its common problems. If you opt not to take the vehicle for a pre-purchase inspection you should bring a check engine light scanner with you to check for any check engine codes. Scanners will also tell you if the vehicle computer was recently reset.
Always take used vehicles for a test-drive, its a good way to get a feel for how the vehicle shifts and what kind of condition the suspension is in.