@ian, there is a set amount of rating your deck gets (5 bronze, 6 silver, 7 gold, 10 plat i believe) when your arena deck wins against someone, they have the option to give it a + or -, + will double the amount of rating. Then when you lose, your deck loses a set amount. (10 bronze, 20 silver, 30 gold, 40/50 plat) <- rough guess
Chadlz, typing a few sentences in response to many questions doesn't take long (seeing how you are quite the one who's picky about time.) and qazzaq123 here has probably played this game far longer than you will ever, it doesn't mean he has no life, but rather because it is a good game