Quick summary - Everyone has the option to get two Trade skills, a gathering skills and a crafting skill.
Gathering SkillsButchery - Hacking up dead animals, used for supplying mostly Apothecary and some Cultivation
Cultivation - Growing plants, used almost exclusively to supply Apothecary
Magical Salvage - Breaks down magic items, used almost exclusively to supply Talisman making
Scavenge - Looting dead people. Supplies Cultivation, Apothecary and Talisman making.
Craft SkillsApothecary - making potions that can enhance any stat in game, provide temporary shields or explosive 'grenades'. Can also create Gold for Talisman making
Talisman Making - Talismans are slotted into equipment giving stat and resistance boosts. All but the best are time limited (in-game time)