Everyone has mentioned the Preflight inspection, but I can assure you that a post flight inspection is important and will save you embarrassment some where along the way.
I learnt the hard way, nothing worse when you were the last person to fly the machine, do a preflight before your next flight and find something wrong which could have been repaired earlier.
Along with everyone else, if doubt ask someone who knows, chances are the instructor only has a few more hours than you do.