This is the final post in the Pet Control guide, updated for Cataclysm.
Part 1 - Attack, Follow and Move To
Part 2 - Aggressive, Defensive and Passive
Part 3 - General pet abilities
Part 4 - Species-specific pet abilities
To begin: there are 4 slots for pet-specific spells on our pet bar.
For me, the 2 left-most slots are the easiest to reach (Ctrl-4 and Ctrl-5), so the abilities I have here are both important for timing and on long(ish) cooldowns, such as Sonic Blast (for timed stuns in PvP) or Call of the Wild (to coincide with burst DPS - Heroism/trinkets/Beast Within etc).
The right-most slots, if not required for the more important pet spells, are either emergency spells such as Heart of the Phoenix or Last Stand, or abilities that I need to make sure aren't on autocast, such as Growl for my raiding pets and Cower for my tanking pets.
Spells that do NOT need to go on your pet bar include things like Bite/Claw/Smack (ie spells that can be left on autocast ALL the time).
Anything left over that needs to be cast manually and you can't fit onto your pet bar, you will unfortunately have to macro and pull onto your player bar.
Prioritizing pet abilities for the pet bar
Ferocity pets are usually used for DPS and not much else. Almost all of their abilities can be left on or off autocast due to their short cooldown, so you generally won't have problems organizing these.
As an example, here's my usual Ferocity DPS pet bar:
In order, I have Call of the Wild, Dash, Cower and Heart of the Phoenix.
Call of the Wild and Dash (for moving pet in and out quickly) are really the only two spells that I need on the bar, since they need to be cast at specific times. Every other spell is on a short enough cooldown for me not to have to watch it.
To fill the last 2 slots I chose Heart of the Phoenix so I don't have to look for it when my pet dies and Cower because you can use it when your pet is taking too much incidental damage (which doesn't happen often in a raid situation, but may do for specific boss abilities like bleeds).
Depending on what purpose your Cunning pet has, you'll need to have a look at your most important spells.
For PvP, this is usually the species-specific spell, since most people choose PvP pets according to these - Sonic Blast or Pin, for example. Of the family-specific spells, Dash, Bullheaded and Roar of Sacrifice are common in PvP specs; you may also have Roar of Recovery.
Wait a minute - that's too many for the pet bar!
Well, if you have all of these, the best one to macro and pull onto your player bar is Roar of Sacrifice. This is mainly because to cast the spell, you need to be targetting someone to cast it on them - using a mouseover, focus or specific player macro can be more useful than having to target someone manually to cast it from your pet bar.
As for Carrion Feeder, it's an out-of-combat talent and it's therefore not essential to have ready access to it. PvPers are unlikely to have this talent anyway, since there are more useful places to spend a talent point; if you're using your Cunning pet for farming you can rearrange your pet bar accordingly (have Growl on there and leave the species-specific spell on autocast, for example).
For me, this is the worst pet bar to organize in terms of how many active talents you can get.
In the talent tree, you can get Charge, Last Stand, Intervene, Taunt, Roar of Sacrifice and Thunderstomp all at the same time if you feel like it, plus your species-specific spell and general pet abilities.
Personally, I only use my tenacity pets for farming or difficult soloing. My turtle's bar therefore looks like this:
In order, Shell Shield, Cower, Thunderstomp and Last Stand, leaving Growl on autocast (I don't have the other active talents; if I did they would replace Thunderstomp). If my turtle had Taunt, I'd put that on the first slot and shift Shell Shield and Cower down one, because you're more likely to want Taunt in an emergency and on an easy-to-reach hotkey than the other abilities.
For the same reason, I recommend putting species-specific spells in the first slot for easy access and macroing Intervene and Roar of Sacrifice to put on your player bar.
And that's it for the Pet Control guide! Feel free to post questions/comments (or email me) if you think I haven't covered something and I'll make sure to get back to you.