There will come times that you will leave specific markets. This usually occurs when competition is furious and profit margins are practically nothing. When you abandon this market, you should still check in on it periodically.
I did just this yesterday and found that there is gold to be made in the glyph market again.
Glyphs are what got me to the gold cap in Wrath. I have barely been selling any in Cata due mainly to one player who drove the prices down to 20 gold a glyph. I got out. Now I am back in.
A single evening made me 3k. I didnt post any glyphs until around 7 or 8 pm. I am now back in full force.
On another gold making note, I bought out 400 stacks of Elementium Ore for the shuffle this morning. They ranged between 19-24 gold per stack. These are the best prices I can remember. The best part is that my competition doesnt get any of the uber cheap ore.