With the last patch pretty much all classes got new glyphs, witch did bring life into that market once again. Duo to the high demand of new glyphs the market is awesome right now !
It's all about being able to sell as many of the new glyphs as possible, the only way to get ahead of the other people on the market is to get your hands on Book of Glyph Mastery.
This means the price of these went up, A LOT! They used to sell for 100-200g on my realm (A medium pop PVP realm) After the patch, they sell for 800-1200g each on AH.
The best way to farm this book is by running wolk dungeons, doesn't matter witch one.
https://i.imgur.com/1Y5QN.jpg
(Got reports of price up to 2000g on other realms)
The new AOE loot system makes the farm really easy and smooth, a lot of greens, cloth and relics will be obtained as well, it all add up.