use scatter or your pet CC to open gaps, use master's call to clear roots/snares and keep them slowed as much and as often as possible. If you're fighting something that doesnt have/apply DoTs Scattertrap and bandage when possible. Go big red and burst em down if you can, or try and force some CDs with Stampede. Save second BW for CC breaking.
Concussive on cooldown, try and save disengages for after grips/charges, scatter defensively if they get too close with CDs up, MC to remove snares, trap to slow, should probably toggle off launcher and drop it at your feet. Snake trap snakes will also put up crippling, but exactly no people ever have ever let snakes live that long.
This is all presuming you're not scattering/trapping someone else, though, of course.
Really though, concussive shot on CD is boss. Its duration is longer than its CD, last I checked.
As far as your question about pets, shale spider WAS great before the patch (3 second stun) but I just went and abandoned all my shale spiders because I can't see the new 90 second cd being worth it for a 3 second stun when I can get more frequent use out of other pet's abilities.
I'd recommend looking through Petopia if you want to see different pet family abilities.