Almost every player that starts this game raids stores as a priority. They see 200k gold loot and drop a full army to get it. The maximum you can raid using this technique is 600-800k an hour. Now that probably sounds like a pretty good result right? Actually it is possible to do a lot better by farming mines instead.
The trick is to get in the right range and not be concerned about losing trophies. Next target players that have gone inactive but have a lot of gold showing. The best indicator for this is sleepy builders and empty elixir stores with no gold showing in the gold stores. Find a base like this and you can attack mines and pumps with fast turnover troops like barbs, archers and goblins. You can use half armies or less and still get your 200k gold loot. You may have to search up to 50 times to find the right type of base but my average is 20 searches.
The beauty of this approach is that mines are normally outside bases and far less protected than stores. Gold and elixir will have built up over time as it won't have been collected. Normally an inactive player will have no gold or lix left in the stores after being full raided once. So any resources left will all or mostly be in stores making it easy pickings. Some players will have built lvl10 mines and pumps filled with resources. Find those and its very possible to gain 400k plus just using 50 troops or less. You might not get the win but you can win one to get those trophies back and still make far far more than raiding stores.
The right range is between 1200-1500 trophies even TH5 players can reach this zone. What you will find there are bases pushing to get the 1250 trophy reward. Some will give up and those are your prime targets. It is possible to gain 2 million gold using this technique, my record is 3.09 million in one hour.
We have a farmer training Clan called "Centum Ludus" where we pass on tips on how to do this and a lot more using a 10 challenges system. Apply on our Clan talk posting for more info on the Supercell forum.