Alchemy
Create raid flasks, combat potions, healing/mana potions, transmuted epic gems, alchemist stones, and utility reagents from herbs, vials, elements, and gems.
Thera WotLK profession library
Open a profession to see what it makes, every major ingredient family, where to farm or buy materials, trainer and recipe sources, leveling stages, weekly tasks, tools, and addons.
Crafting and production
Each guide maps the trainer, leveling stages, recipe sources, exact known tool materials, finished-item uses, and the farm-or-buy decision.
Create raid flasks, combat potions, healing/mana potions, transmuted epic gems, alchemist stones, and utility reagents from herbs, vials, elements, and gems.
Forge plate armor, melee weapons, shields, belt sockets, weapon chains, shield spikes, profession tools, and raid-pattern epics.
Disenchant gear into dust, essences, shards, and crystals, then enchant weapons, armor, rings, gloves, boots, cloaks, and profession vellums.
Build goggles, bombs, sappers, scopes, mounts, repair bots, Jeeves, wormholes, ranged weapons, and powerful glove/belt/boot/cloak tinkers.
Mill herbs into pigments and inks, then make glyphs, scrolls, vellums, Darkmoon cards, off-hands, shoulder inscriptions, and raid utility scrolls.
Prospect ore into gems, cut common/rare/epic gems, craft rings and necklaces, make statues and trinkets, and use Dragon's Eyes for profession-only gems.
Convert leather, scales, chitin, and fur into leather/mail gear, armor kits, drums, quivers/bags, cloak/leg enhancements, and raid-pattern epics.
Turn cloth into bolts, bags, cloth armor, spellthreads, flying carpets, specialty cloth cooldowns, and raid-pattern epics.
Cook meats and fish into leveling food, personal stat food, feasts, and quest items; Northern Spices and daily recipes control endgame progression.
Convert cloth into bandages for out-of-combat and emergency healing, progressing from Linen through Frostweave and Heavy Frostweave.
Gathering and supply
Use the individual guides to identify zones, node or creature types, rare side-gathers, tools, route addons, and Auction House checkpoints.
Gather herbs from starter zones through Northrend, including the high-value Lichbloom, Icethorn, and Frost Lotus needed by raid consumables.
Mine and smelt ore from Copper through Titanium, gather stone and gems, create Titansteel on cooldown, and supply three major crafting professions.
Skin beasts, dragonkin, and select creatures for leather, scales, chitin, and rare Arctic Fur used in Leatherworking and raid gear.
Fish anywhere for skill, but target pools for valuable cooking fish, daily quest items, mounts, pets, achievements, and tournament rewards.
Pin the recipe, source every reagent, compare the finished item against material cost, then craft a single test item before batching.
Use GatherMate2, Routes, and TomTom; build loops around the materials your guild and crafting professions actually consume.