I presume your a warrior so it's really up to you. Warrior has Arm/Fury/Prot in their talent tree, choose one as your main focus.

Arms is good for good consistent damage and the Mortal Strike is good too. Fury allows you to generate rage at a very fast pace e.g. 50 rage in less than 1 sec. Prot is only good for PvE instances if you're a tanker for your guild.

As for your mage friend, it's kinda hard to balance his talent tree as you're playing on a PvP server. For now, I suggest him to be a frost/arc mage. If he wants to PvP at max level, then respec to Fire/Arc.

Just a tip is stay at friendly territory until you reach say level 30+ or else you'll get ganked and corpse camp.