The perfect 2 talents to explain this, are Frenzy and Focus fire. Your pet is constantly gaining its Frenzy effect, until the point where you can unleash your Focus Fire, gaining a lot of benefits to yourself. Mixing this in with Longevity, to decrease your pets, and your, cool downs to make you both more lethal is a huge bonus as well. Also, with Invigoration and Go for the Throat, any time you critically hit with auto attacks, your pet gains Focus, and any time your pet critically hits, you gain 6 Focus. Now, I know that a lot of people say that Killing Streak is a necessary talent, however I have a lot of reasons why I don’t take this. The main, and most important reason, is because most mobs you kill only need 2 Kill Command attacks to kill, so if both critically hit, the 3rd is generally wasted. Also, for PvP, the enemy usually gets to be too far away for you to use this, due to the fact that it has a 10 sec timer on it, and Kill Command has a 6-8 sec cooldown so really only a 2-4 sec window to use this talent, that requires 2 talent points. So not worth it.
Since this spec gets messed up if your pet dies, you have Spirit Bond, Improved Mend Pet, and Glyph of Mending to make sure to keep your pet alive and well. Also, remember your Master’s Call and Bestial Wrath in case somebody attempts to crowd control you or your pet. If you want some higher survivability, then I recommend removing Pathing and Improved Kill Command, to take Hunter vs. Wild, and Crouching Tiger, Hidden Chimera. This may reduce some of the damage you deal, but will HIGHLY increase your chance of surviving for PvP, and for groups of enemies.
One thing that I enjoy doing with this spec, is waiting for my Focus Fire to be ready to use, then I follow that up with Rapid Fire and Bestial Wrath, to deliver quick and massive blows with my gun (since I use a dwarf, I like the extra 1% extra critical hit chance with them) and can usually get to approximately a 1.5 sec speed or less 🙂
In PvP I usually use my Chimera (named Thunderfrost). It keeps my enemies slowed down so I can just keep shooting at them. For PvE I use my Worm (named Cupcake) due to its ability to increase enemy physical damage taken and is also a very effective tank. I do however have a Devilsaur (Tyrant) that I use occasionally, as well as a Rhino (Mittens) in case I know I am with some people that do bleed damage, or that I need some knock back.
All in all, this spec has all that you need to fight with your companion against any opponent.