A second city farm
One way to boost your resources quickly is to start a second account. It only takes a few hours to build up a city so that all the resources tiles and buildings are level 5. These will continually produce resources even while you are logged out. You can put this second city in your alliance and use the marketplace to send resources (with taxes). Another option is to just attack this city with your main village to get the resources without losing to marketplace tax. You can keep your Storehouse low in order to be able to get some resources when attacking or you can knock down the Storehouse to zero each time you want to farm out the city completely. Managing two accounts is more work but it can be worth the reward. Once the second city is built up you don't have to do much with it except extract the resources. If you are only going to have a second city I suggest you build a mix of all resources so that you can be balanced in your main city. You may wish to build slightly more stone as this is required for walls and strongholds in greater quantity. You only need to build 1 of each type of building (eg barracks, hospital) to meet the requirements of other buildings. This allows you to build many villas (up to 17) depending if you want a altar, prison, hall of war, embassy). Farm cities don't really require these other buildings because they don't need troops or defense.
The 5 city setup - Hyperfarms
If you are feeling adventurous, and have a lot of time on your hands, you might want to build 5 cities (ie 5 accounts). One primary city and 4 farm accounts. Each farm account can build all of one type of resource (eg ore). In an ore city you'll still need 1 wood, 1 stone, and 1 food resource to meet the requirements of building your city. With this specialization of a single resource you can focus your research and hero points on that single resource. At high levels, these hyperfarms can produce millions of that single resource per day.
Managing 2+ Accounts - Bluestacks
You have a few options when playing multiple accounts. If you only have a phone or tablet then you'll need to logout each time you want to swap accounts. This can be a bit of a pain. One way to get a second account running at the same time would be to install an android emulator like Bluestacks App Player on your PC or Mac. The program is free to use if you periodically install apps inside the emulator, or there is a $2/month fee. Since most PCs have lots of hard drive space, it's easy to just install the apps and never use them. You can always uninstall Bluestacks and reinstall to clear up space if needed. One major advantage of this emulator is that it will run Game of War much faster on a high end PC than on a tablet or phone. There is one bug with Bluestacks currently when entering text inside the game. The text will not appear in the input box but instead will appear in the top left of the screen. This makes it difficult to login and chat but not impossible. I've sumbmitted a bug report to Bluestacks so hopefully this will be fixed in the future.