Agility > Mastery > Critical Strike > Versatility > Haste
Agility: Increases the magnitude of your attacks and abilities. This is your most important stat, which is why you want to look at the item level of each item rather than the stats on it. A higher item level is usually better because it gives more agility.
Mastery: Your mastery is called Mastery: Sniper Training, increasing the range of all your ranged abilities and the damage of all abilities. It affects most of our damage and is usually our best secondary stat.
Haste: Increases your auto attack speed, increases focus regeneration, reduces the cast time, and the cooldown of Aimed Shot. Not bad, but we have better stats choices for MM. In AoE situations, make sure to have enough haste to be able to cast 2 Aimed Shots and 1 Rapid Fire during your Volley window.
Critical Strike: Increasing your chance to critically hit with all spells and abilities. It synergizes really well if you play with Master Marksman and Improved Kill Shot talents.
Versatility: Increasing all your damage and healing done and also decreases all damage taken. This can provide a bit of survivability that is sometimes needed for hunters.
The best way to calculate stat priorities for your character is to "sim" your characterFind out how to sim
Troll outperforms other races by a mile thanks to its cooldown, Berserking, which can be lined up with Trueshot.
Tauren is also really good for BM hunters: it gives you a 2% critical strike passive and more survivability with the endurance and the 1% nature damage reduction (we are weak in terms of defensives, and all the raid is about nature damage).
Human is also a decent choice for Alliance players thanks to its The Human Spirit passive, which provides 2% more of all secondary stats.
Cloak: Enchant Cloak - Graceful Avoidance
Chest: Enchant Chest - Waking Stats
Wrist: Enchant Bracer - Devotion of Avoidance
Legs: Fierce Armor Kit
Ring: Enchant Ring - Devotion of Mastery, Critical Strike, Versatility or Haste (depending on your stats - SIM yourself!)
Weapon: High Intensity Thermal Scanner
Every gem with 2 different stats works (these provide more stats than the single-stat ones). It is situational and will depend on what stats your character has at the moment; the best way is to SIM your character on Raidbots to see which stat you need the most. Make sure to have 1 Diamond equipped (this one is more powerful).
Food: Grand Banquet of the Kalu'ak
Flask: Phial of Tepid Versatility or Phial of Glacial Fury (situational)
Potion: Elemental Potion of Ultimate Power
Rune: Draconic Augment Rune
Healing potion: Refreshing Healing Potion
Weapon rune: Completely Safe Rockets