Land Rover and Jaguar Thornhill

1. DO YOUR RESEARCH

This first mistake is very common among buyers.

The best way to get the knowledge you need is by consulting well-established magazines like Car and Driver and Road & Track, JD Power , or a personal favorite Top Gear. You can also check the latest reviews by browsing the Web and checking out many interesting sites.

Another great resource is Consumer Reports, the automotive section, you'll find reviews, ratings and recommendations on used AND new cars. 

 
Finally, research the resale price of the car you're interested in. Land Rover's and Jaguar's historically have high resale values, in particular, the Range Rover Sport and LR2 have the highest residuals in their class.