Second year ski instructor here, not PSIA though. It's a good job over holidays when all the people are there, and if you are professional and nice your sups will start to hook you up with the good privates. I got a private lesson this Christmas that landed me a $1,000 tip. Patience is the name of the game. You will struggle to grasp how some people can possibly be so bad at skiing or have such bad athleticism in general. Lower your expectations and go to your happy place. Explain things in simple terms, and if possible relate it to things that your students know. When it comes to kids, make sure they're having fun. Safety, fun, and learning are the most important things in that order. Keep everyone safe, try to make sure they have a good time, and hopefully they'll be able to learn something to. Obviously if you teach intermediates or above you will have to actually deliver with your instruction but that's probably not a concern for you if you're just starting. Generally those lessons go to certified instructors. Getting certified is probably a good idea if you plan to continue to teach multiple seasons, but even if you don't get certified, go to the training for the certification courses (it's free at my mountain, talk to your sups). It will really improve both your instructing AND your personal skiing. You may not think that doing wedge chrsties and side slips will help your skiing but it will once it's beaten into you, especially in the steeps.
Have fun and enjoy yourself. Don't lose the kids.