of Orgrimmar/Undercity/Silvermoon/Thunder Bluff/Sen'jin*
*Sen'jin is Darkspear Trolls and is the name of the troll starting village in Durotar.
Do all the quests for that faction. Yes, all of them. You can see who has low level quests by clicking the tracker button on your minimap.
Go to the appropriate faction page on Wowhead (alliance/horde) and sort quests by ascending. You'll have to scroll past the holiday quests to get to the normal ones, but then you do them all in order of level.
The availability of these depend on your level.
Wool x60, Silk x60, Mageweave x60, Runecloth x60.
Repeat Runecloth turn in for 75 rep/stack.
If you don't want to do this rep grind or have already done it:
Farm Runecloth and sell it. You will make THOUSANDS, particularly right after the tournament event begins, when people are desperate to get their rep up.
If you refuse to take advantage of this opportunity, you don't get to complain about never having money. You just don't.
 More details about the tournament. It will be a permanent event and part of it will come out later than 3.1. Not sure about what "permanent event" means, as Zarhym was pretty vague:
It's going to be a permanent event. You will be working to construct the coliseum, though the coliseum itself will officially be added in a future content patch.
You'll see more competitions and festivities coming down the road as well.