There are several ways to win free Gems or Jewels in Clash of Lords.
1, Complete Quests. Tap the Girl Icon at the left screen and you will find a list of quests, just follow the quest instruction and complete all quests to win Gems.
2, Participate in Events. Click the Gift Box at the right screen and you will see available events. Just Rate the game, give the game 5 Stars and leave your comment to Win 100 free Jewels. By joining "Race for Top 10 Players", you will win tons of free Gems /Jewels.