Tips for earning currency on Clash of Clans [duplicate]

If you don't mind losing trophies, a good strategy is to put your town hall on the outside of your base. Then using a bulkhead base design, focus all of your defenses to protecting your resources.

I typically hover around 1k trophies this way. Most people that attack me will just go for the Town Hall and leave my huge defenses alone. This gives me a free 12 hour shield when they do so as well.

Just a note: if you cannot protect your resources at Town Hall 7, then you're going to lose even more resources at Town Hall 8. The bigger the difference in Town Hall levels between players greatly affects how many resources they can take.

(Free way)Enter a clan that requires nothing to subscribe to, and improve your defense, specially invest in your city walls. If you win wars your clan receives money you can cash in afterwards.

If you are willing to spend some bucks on it, first upgrade all your gold mines until there's no more upgrade you can make, then buy a short-span shield (1 day, 3 days) and boost all of your mines (gems required). This could help you achieve a huge amount of gold in a short time.