Don't stack your blocks too much. If you've already filled up your queue, it is better to attack however you can. 3-block chains are always the most effective attacks, but you don't have to do them at all costs. Sometimes even smaller attacks at the right time can mean all the difference. If your hero has the ability to attack all of the nearby enemies, wait for the right moment to strike. You would want as many enemies around you as possible. You can get free heroes by completing daily quests. You have to do it before they reset, though. Be helpful. Aid your friends in the battle and you will get honor points, which you can use to buy hero packs. Learn what each hero does. For example, Shaman can heal another hero by sacrificing his own health. This makes him quite useful, especially early on in the game. When you level a hero to the maximum, you get a reward of one gem per hero. Because of that, it might be wise to wait a bit till your group gets larger.