Why won't my 2011 Honda CR-V start?

I just bought a used and certified 2011 Honda CR-V from a Honda dealer. Once we got home we left the car in the driveway for about an hour. I went to go turn the car around in the driveway and it would not start? My mom thinks she left the lights on maybe but would a hour of leaving your lights on really drain the battery all the way dead? Whenever I tried to start it, it would just make a clicking sound and not start at all. What's wrong with the car?!

(My mom test drove it and she liked it, then I drove it around, and then she drove it home. The car started all three times perfectly).

What to do to keep my car in good condition?

I have a 2006 Honda CRV with about 83K. I'm in college and really want this car to last til about 2018-19. I wouldn't be able to finance another car. Anything other than routine matintence and oil changes to increase the life of my car?

What are the top high gas millage cars today?

It should be reliable & safe. The CRV used to get about 50 mpg long long ago, but where is it and what does it get today? I heard the Honda Insight isn't made any more, but it seems to be, it's just not getting the gas millage it did when it was first released. The Prius seems like the obvious choice at 50 mpg, but I'm not very fond of its lack of style. The Cooper gets pathetic gas millage and is too expensive. What are the top 3 models I should consider?

Honda CRV fuel auto vs manual?

Hi, I'm going to buy a Honda CRV 2000. Have heard that auto and manual both does same on fuel. Just wanted to verify.

Going from V6 to V4 engine?

I currently drive a 2006 milan with a V6 engine. I'm looking at new cars, and I think I want something along the lines of a honda crv or nissan rogue because of their size and all wheel drive. The issue I noticed though is those cars have a V4 engine. How much of a difference would there be between those kinds of cars and my current one? Would it be a big difference I would notice?