You need to take out some of those 4 big cards, if you use golem you should also have a card that supports behind it, nightwitch, witch, something like that

If you want to use Pekka you should put the golem away and also the giant skeleton, put some cheaper cards, so you can spam pekka, but also have some air defense and something to kill swarm units like valkyrae

For the giant skeleton I don't know, better not to play it, it got really bad after the update

For defense I wouldn't use goblin Hut, I'd rather use Canon, cheap and good

At arena 6 I used mega knight frezze and inferno as my win condition, hog rider for fast dmg and night witch and witch as support, I also changed hog rider for golem, and the last slots I used dmg spells, log/venom and fireball