How to choose a new car for a newbie?

Attempting to search for a new car. Currently,looking at 2017 Toyota Corolla LE. How do I exactly choose a new car that is right for me? It is less than $20k at a dealership near me but I know the salesmen will try to make me buy more. How do I prevent that? via /r/cars http://ift.tt/2tKQuVp