How to get better?"

I'm in post game now and its been very hard. I get defeated very easily against Almakarma the Awakened and other bosses like Shuguluna the Infinite. The classes of my allies are the same, Rabi is a Striker, Tirma is a Warrior, Nyx is a Thaumaturge and Uula is an Acolyte. Rabi and Uula are level 39, Nyx and Tirma are level 40. What should I do? Also whats the best place to farm exp and gold?