Want to steal a city and are at your max?  Want to persuade a stolen hero?  Of course you don't because you're all sweet hearts (I won't judge you for your dirty deeds)!  So to medal farming, one of the most fun aspects in the game, only seconded to food farming. 

Okay, so there are two main methods for medal farming.  I have done both methods and have good results using both.  The first method is a simple scout a valley and use a predetermined attack with laying, the second method involves attacking a valley right next to your city multiple times.

Method 1

This method involves scouting all level 9 and level 10 valleys around you.  When you get the report, follow the setups below:

a) Warriors/Pikeman/Swordsman: Attack with 25,000 Archers, 1 Cavalry, 1 Scout.

b) Archers only: Attack with a matching number of Cavalry, 1 Scout

c) Cavalry only: Attack with 40,000 Archers, 1 Swordsman, 1 Pikeman, 1 Scout, 1 Ballista

d) Cavalry + Warriors/Pike/Swordsman: Attack with 50,000 Archers, 1 Swordsman, 1 Pikeman, 1 Scout, 1 Ballista

e) Avoid any combos that has Archers plus other units.

Casualties for the combos above:

a) 1 Cavalry

b) 1 Scout

c) Possibly 1 Swordsman and 1 Pikeman

d) Possibly 1 Swordsman and 1 Pikeman

e) If you do attack, you will lose atleast a few thousand Archers.

Method 2

This method involves having a level 9 or level 10 valley extremely close to your town, preferably right next to it.  You will need to have one free valley spot (so you can capture it) with that town.  This method also will result in more casualties than the previous method but does yield medals faster as you will hit the valley more times.

The most common used combo is 25,000 Archers, 1 Swordsman, 1 Pikeman, 1 Scout, and 1 Ballista.  What you do for this method is send out the first attack, wait 10 seconds and send out another and keep doing that (add a little more time if you are lagging).  When the first wave hits the valley and you conquer it, abandon the valley.  Abandoning the valley will cause the troops to respawn right away inside it giving you another shot at a medal.  Do the same for each wave attacking.  If you plan on doing this for multiple days, hold on to the valley during maintenance so that it won't level.

There are a few other methods out there but these are the two most common and the two that I have the most experience with.  Good luck with the farming!