I made it to 4000 trophies with my level 8 mini account with this deck
Goblin Gang 11
Goblin Barrel 10
Baby Dragon 7
Spear Goblins 7
I made this account to request knight and goblin gang, so my main account and clanmates get star points, that's why the card levels are very strange.
It is still pretty cool to be in the league with a level 8 account anyway, so it is probably worth sharing.
People below 4000 are mostly noobs, they hardly ever save their small spell for the barrel, and they do not know how to defend barrel with troops. Just stay alive and goblin barrel will eventually win the game.
With these card levels in 4K. Fireball does not kill Magic Archer. Baby Dragon does not counter Minion Horde. Balloon, RG, Lavahound and Golems are unstoppable.
But opponents will ALWAYS make a lot of mistakes, stay positive.
Overall, It was a quicker and easier journey than expected. Only 247 wins in this account.