There is lot of farming guides for Clash of Clans. You can use lot of troop combinations like barbarian – archer or giant – wall breaker – healer. Or even with dark troops. Mass hog riders will crush a base easily. However, not all of the them are cheap in resource and time. Personally, I like to use goblin – wall breaker combo. It is the cheapest and most effective way for me. The best way is to find inactive base with gold mines and elixir collector outside of walls that full of resources. You don’t need to use any wall breaker then. Else few wall breakers to open the path and use goblins to steal resources from storages within the walls.
Of course, this combo does not work well on highly defense base. And you will lose the battle without winning any trophy. But you get high resources in return in fast and easy way. Do make sure that you are farming in the correct trophy range too. Well, that’s it. This is the method that I use to keep my gold and elixir storages full all the time for upgrades.