I always upgrade everything to maximum when playing games. You will get most of the attack power and defenses then. Same apply to Clash of Clans. I am at Town Hall 7 and got all my dark elixir required troops upgraded. Thanks to How to farm dark elixir in Clash of Clans? guide.
How to get Barbarian King at Town Hall 7? In short, get it with 10,000 dark elixirs. No need to use gems or real money. Just raise your trophies and raid for dark elixir. And do upgrade dark elixir storage to level 2 to make it harder for others to steal. I managed to get Barbarian King in 3 days. You can get it with less time.
