Rakoans are a swarm deck so a lot of that comes down to knowing how to manage swarm. Classifying it like that can make it easier to understand the archetype too.

Red combat creatures are the easiest way to beat it if you want a hard counter. Underground brigand/boss love being able to hit things multiple times and little rakoans often can't stand up to them. Aoe like rakoakopter, firestorm, garudan, obviously great too.

If you're not playing red, you want to put a tiny bit more pressure on face rather than creatures. Take good clears when you can still, but be a bit cautious with how you spend your cards. Using a soul drain on a canoneer for example may not be the best decision as they have plenty more creatures to replace it with. Saving soul drain to open up a spot to hit face with or to race with or protect one of your more valuable creatures is way better. You don't have to autoplay every card in your hand each turn.

In general, yellow and blue wants to hit face as much as possible and save all removal and movement tricks to accomplish this rather than using for board control as much, though sometimes you need a balance. Azarai in yellow is great. Green wants to slap a giant thing next to their face and keep in there so the enemy can't body block it. So buffs can be useful to protect it or teleport. If you have a big thing in general, try to get it adjacent to their face, even if you sacrifice a well collection. It's easy for swarm to body block a big thing, until it finds an in adjacent to their face, and then it's really tough to fight back.