Pandamonius' Comments

If you don't have a Terrible Turnip, you need to get one immediately!  This pet is what you build your capture team around.  Sunlight doubles the health pool, thus doubling your capture window, and Weakening Blow will not reduce the enemy's HP below 1.

Give your target a couple whacks (no DoT's) with your big guns, then whip out the turnip, turn on Sunlight, and give another whack or two and you'll never again accidentally kill the pet your trying to capture.

For those aspiring to catch her, I highly recommend you get a Terrible Turnip!  Between Sunlight (which doubles the max health pool, thus doubling your capture window) and another one of the Turnip's attacks (which will not reduce the opposing pet's health below 1), the Terrible Turnip is the most important part of your capture team!