Play games
Choose the game that interests you and play itfor free.
Complete the quests
Every game has some quests for which you will receive Soul Gems.
Receive rewards
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
Since there are low paying offers or sometimes no available offers in my country, I couldn't earn enough soul gems to get rewards. So could anyone tell me a best way to earn soul gems ?