When i first got my mage to 70 i was a baby in cloth, i got owned by everything including warriors 0_o i was literally sucky and very bad at pvp, i couldn't kill anything 1vs1 because i simply didn't know how to...
After watching vids, learning how to pvp getting advice from other mages i got the hang of it, and now im much better and can take on most classes including locks D:
The 10 things you will face/have to learn as a mage is:
1) You will face painful times when you hit 70 trying to farm your pvp gear and vindi, but always die in the process simply because of your gear
2) You will think you suck and blame classes being overpowered etc. but then you actually realize its your fault! (this takes a while)
3) You will need to learn when to use certain spells at what time, by watching vids, and learn how to counter abilities from different classes
4) Will need to learn WHEN to use ice block and you pvp trinket (thought this was not important, but it REALLY is when you come to think of it :S )
5)Build your OWN strategies against other classes (sounds stupid...but it works)
6) Learn to not cry when you get melted by a lock or a huntard D:
7) Face painful times in your first arena team
8) Learn to NOT dps in arena alot, but CC more often
9) Make your OWN talent build which YOU think is good (not by just going here and looking for a talent build thread) This helps alot, because making your own doesn't make you regret how many points you put in what etc.
10)Facing against pesky s3 rouges in Isle of Quel danas getting ganked all the time while your trying to earn gold :P ( and learn how to beat them somehow...vids advice from others etc.)
As a mage you have low survivability and have to think of ways to AVOID getting hit, thats our main power, if you master this along with good timing by using trinkets ice block etc. you will own badly...