I saw Swervo mention this and thought it was a good idea. So I will go ahead and start it.
whenever someone mentions they are looking to replace a vehicle, I go through an algorythm. It looks kinda like this.
What kinda of vehicle are you looking at? What is it's main purpose?
What is the most required detail of said vehicle? (I.e. space, luxury, fuel economy, price, flair and flash, safety, etc)
What is your dream vehicle that you are currently looking at and why?
What are some absolute no-gos? (you don't want X manufacturer, no minivans, etc)
What is your price point you are comfortable spending?
Lastly, what hobbies, or dreams do they have, and does this vehicle choice fit that plan in the next 3-5 years?
From there I break down what vehicles fit into that very general information package. and then slowly rank each option one by one.
THEN I have them go and drive each vehicle. I have seen to many times where someone goes and drives their vehicle of choice and they actually hate it. Seats are uncomfortable, driving postion is weird, "it's too big".
From there I am able to help guide them to a vehicle. I have done this a few times, and it is shock how well it has worked out.