The iDOLM@STER, Wake Up, Girls! Shichinin no Idol Recommendations
Both about Idols trying to get popular
Encourage, morale, feelings, smile, all these in how to become a successful Idol. But the two most important aspects in becoming an Idol is the powerful of friendship and inspirational spirit. In the story, it follows a main male character who is surrounded by an all female cast characters, training to become Idols. Each day, depending on their schedule, it is "Practice make Perfect," where they practice and get ready for the real event with all their energy.
Not much of a difference but The Idolmaster features a large cast and some comedy, while Wake up Girls features a small cast, with some drama moments.