IMO, this guide is very basic and does not cover a lot of important things.

The basics:

Make sure u install spellalert or enemycastbar so u can use earth shock to interrupt spell effectively.


Warrior:

Use a shield!
He will charge and hamstring u right away. So u need to use pvp trinket to get out of hamstring then frost shock him, drop earthbind totem and kite him. How do u kite? U need to use the Q/E button to run away and then use your mouse to rotate the camera in a way that your char will always face the opponent while u running. Why u need to do this? Coz Q/E button is RUNNING in side way A,D is just WALKING. Also u need to always face the opponent so that u can shock them, shock needs u to face your opponent.

Actually u can out melee a warrior if your gear is ok. I can out melee most epic warrior with my rank10 pvp gear except those who has hand of rag or askandi.
Drop stoneskin n magma totem n then just melee + earthshock. Heal yourself when ur hp down to 50%. I think u will be able to beat a lot of warrs.


Pally:

Use shield unless u have good 2 hander weapon.
Ok i think what that guide told us is down to useless against a pally who know what he is doing. The key to beating a good pally is mana efficiency.
Do not drop any totem except earthbind. Just melee with them n don't do any shock except rank1 earthshock to interrupt their heals. Heal urself when u r down to 30-50% hp n u need to drop grounding totem b4 u heal urself so that the pally can't stun u while u try to heal. And u can use healing wave here to conserve more mana coz the pally cant interrupt ur heals with grounding totem on.


Grr... i m abit lazy to write the remaining classes. I think there's a lot a lot more details for shaman pvp which is totally left out at tht guide.
I recommend checking out some shaman pvp movies:

1) Sham - best shaman kiting skill
http://www.warcraftmovies.com/movieview.php?id=4079

2) Ueunaydar - best shaman in my server, i never saw him lose a duel, superb timing on shocks n totem use
http://www.warcraftmovies.com/movieview.php?id=2091

Btw, i am gonna roll a Dranei Shaman in exp. SHAMAN FOR LIFE