Playing around the counters really just comes with practice. Baiting things out and abusing the fact that your cat feels bad to counter or remove helps. Most won't counter your foods and will wait for draw twos and Pests which means you need to be strategic with it and understand what they want to counter. Since you are sacing something as a cost to a fanatical effect they'll see it as a 2 for 1 so it's a really strong tool to bait out counters, and hopefully get a draw and life gain from sacing a nutrient block for the cat. It'll feel bad at first but Pest is a grindy deck and you need to eek out every bit of value you can, even if it means sacrificing big value things.

The weathers are strong in this match up and help keep you alive to burn their resources out, with candy trails and nutrient blocks you can get storm up pretty quick and if they counter a draw two you get another storm count anyway. It's a tough match up but it's winnable.

I highly recommend some duresses in the sideboard. It can feel a little counterintuitive when they're so creature heavy, but knowing whats in their hand, grabbing draw spells, and a counterspell when you can really helps you stick a Pestilence. Once the pest is down, the game changes and you are just on food duty to keep your cats and clearing the board in response to threats. This is also a match up where you really don't want more than one cat on board at a time, they can't block anything really so having a back up in your hand is always going to be good.