You should do 1-2 lessons every now and then. The lessons are worth more as you progress through the game so it's pointless to do them all in the beginning. I would throw a communication whenever you run out of memories.
Eeee thank you! Got rank S with a few weeks to spare and did the pointless season auditions too! (still didn't get the achievement, since I haven't gotten the Spring one yet...grr). That 700,000 Idol Vision audition also helped a ton, trying to not rely on the communi's that much, kinda hard though on some auditions, even if I try to sabotage it.
I am trying to play through the game a second time. Started a little rough, but the guides are helping me get memories, and understand the background of each girl.
I have a question though. Obviously changing the song (and outfits?) affects the idols, so am I suppose to find a song they do good at, or am I supposed to change eventually?
After about 10 weeks, the idol starts talking about a new song (or whines about the old one). I think finding a song they like or they "own" helps tension (not sure, my tension's usually full anyway).
Outfits also affect their stats. If you can get an entire outfit (i.e. Taiko head/body/hands/legs), it'll give a stat bonus as well.
Huh, that was some info I did not know about. Thank you, I am going to work on the game some more tomorrow and see where I get,I have been too busy to get on lately.