Did it 6 times yesterday so I'd like to share with you my guide (such a big word for such a small thing ) for Alchemy 450-525. I take into account several things and by far not at all the "fastest way". It takes into account the market price of herbs used, the relative interest of the crafts and of course reaching the goal NOW!

Skill
450-460 Ghost Elixir - 20 Cinderbloom
460-465 Volcanic Potion - 5 Cinderbloom + 5 Azshara's Veil
465-475 Elixir of the Cobra - 10 Cinderbloom + 10 Azshara's Veil
475-480 Elixir of Deep Earth - 10 Heartblossom
480-485 Elixir of Impossible Accuracy - 5 Heartblossom + 5 Cinderbloom
>>>> Transmute: Living Elements (in case you don't have the materials to Truegold, do this now)
485-490 Potion of the Tol'vir - 5 Stormvine + 5 Whiptail
490-495 Golemblood Potion - 5 Volatile Life + 5 Heartblossom
495-505 Elixir of the Master - 10 Twilight Jasmine + 10 Heartblossom
505-510 Transmute: Dream Emerald - 15 Jasper + 15 Stormvine
510-515 Transmute: Ember Topaz - 15 Hessonite + 15 Cinderbloom
515-520 Transmute: Demonseye - 15 Nightstone + 15 Twilight Jasmine
520-525 Transmute: Amberjewel - 15 Alicite + 15 Whiptail

Thanking you in advance for your attention.
A.