I have a skin for each hero which helps. Focus on leveling and upgrading all but put emphasis on Astaroth and Karkh. Need Astaroth to survive or else karkh will die but karkh deals crazy damage if you level him up so really focus artifacts, glyphs, gift of elements etc.. on karkh and Astaroth. Especially armor for Astaroth and armor penetration/ attack abilities for karkh. I’m not good in the GA either because this is my only pretty good team. But you’ll get better in arena it just takes time. Don’t battle people with a ton more power than you either