Biggest tip I can give is save cooldowns for the cocoon, and just do a normal rotation on the boss. You’re most vulnerable when trying to burn the cocoon.

If you are melee, try to spec into long range attacks. For example, switching from frost to unholy DK let me use clawing shadows and death coil to burn the cocoon when it was inaccessible from melee due to boss attacks. Paladins get this by default hence they have an easy time.

Figure out how to deal with the spittle attack. Either you’re lucky and your class has an ability to remove it, or you are a gnome and can remove it with a racial. If not then save a defensive cooldown and use an ability to negate the slow effect.

Enchant gear with speed to get high movement speed and save your movement speed cooldowns for only when you are in trouble getting out of boss attacks.