PK line score is gained or lost by giveaways and takeaways.
It's important to manage the puck and not turn it over. If you can be safe with the puck, and take away the puck more then you give it away; you'll gain PK line score.
So, try not to force passes, lose the puck and opposing team recovers, etc. and take away the puck by stick lifts, bump/check and recover puck, etc.