Gather focus question.

[GamingGoddess32]

Forgive me if this is a silly question. I currently have 3 characters and I've been playing since the english launch.

My question is: How do you properly gather focus to execute your RMB attack? I can't seem to figure it out on my summoner and destroyer. There's no indicator as to how much I'm gaining as far as I know. Unless I'm missing it. It doesn't always happen, so Idk what I'm doing wrong. X_X

Thank you. D=