Unless you shell out BIG bucks for trans scrolls when you can find them.
Little shortcut I found tho, buy some Alacrity scrolls. Tame until you get a gain. Log off and wait a day. Log back on eat the alacrity scroll, tame until you get a gain, go log off. Keep repeating with a day difference until that Alacrity scroll runs out, it usually only took me one or two tames to snag a gain that way. Most think it is a real world 15 minutes. But, it is actually an in game 15 minutes. At least it was here a short time back and have not heard anything about it changing. While it drags out the grind over time, it's way less boring than grinding, grinding and grinding. Worked fairly well for me, and freed me up to do other things than tame all day long wasting gold on alacrity's for only one or two gains during each 15 minute window.