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.
More training is the best way to be better, trust me. Try and repeat again and again, know every detail about the song, your muscle will remember every time point. I think that is the key to win.