There are 2 things that you can do to improve your stats in The Idolm@ster 2. The first option depends on the costumes and accessories that you have on your unit. The second option is by having your unit take lessons. You can only increase each stat to approximately 60% of the stat bar that is shown on the top right of the screen. The rest of the stats beyond that need to be from costumes and accessories.
There are three kinds of lessons in The Idolm@ster 2: one to increase vocal stats, one to increase dance stats, and one to increase visual stats.
Two options exist for each of the 3 lessons: a regular lesson or a super lesson. The two versions of any one lesson are exactly the same control wise. Super lessons cost more money to select, but they give you more time on the clock to try to fill the bar up. You will also receive a higher stat increase than the regular version of the lesson.
If you would like to further increase the amount of stats you get from each lesson, try getting the reporter named Koshiba Tooru.
Starting on your second playthrough of the game, you have the option to tell your unit to do the lesson on their own. This will save you time, because you don't have to do the lesson yourself. However, this is not recommended, as you can't control how much of the score bar your unit filled up (it can be anything from bad to perfect) and there is the chance that they will get tired and not show up to work during future weeks.
Vocal Lesson[]
Vocal Lesson - Click to Enlarge
The vocal lesson looks like a wavy musical staff, with notes that look like the A, B, X, and Y buttons on the controller. These notes can scroll from either the left or the right. The objective of this mini game is to hit the button on the controller that corresponds with the button that the note says on it while it is over top of the icon that looks like a microphone.
When you successfully get through each section of notes, a bit of your score bar will fill up. You can keep playing until the timer on the upper right of the screen runs out. The more of the score bar that is filled when time runs out, the higher your vocal stat will increase.
Each time you miss a note, the notes will rewind back a little bit and one of the girls in your unit will get frustrated. During this time, the time on your clock keeps ticking down. You get 3 tries (to correspond with your 3 girls in the unit) to get the current section of notes right. If you can't get it right in 3 tries, you will get either a small or zero (depending on how much of the note section you hit) increase in stats.
You can hold the LB or RB shoulder buttons to make the notes scroll faster. This is useful so you can get through each note section faster. However, this is completely optional to do.
If you manage to fill up the bar all of the way, you will see the word BONUS! flashing on your score bar. This means that you will get the maximum amount of stat increase that you can receive from that one particular lesson.
Dance Lesson[]
Dance Lesson - Click to Enlarge
The dance lesson looks like a bar with the letters R and L on it. You will hear a metronome-like count off at the beginning of each bar section. The objective of this mini game is to hit the R and L shoulder buttons in the order that is shown on the bar. However, you must hit them in time with the metronome. The metronome is 4 beats (think of counting to 4). You should start pressing buttons what would be the 5th beat.
Button presses that you get correctly will show up as pink footprints walking to the right. Button presses that you get wrong will show up as blue footprints going a bit diagonal. The game takes the number of pink footprints you got on the bar and will fill your score bar based on that. So, the more button presses that are right, the better!
The timer continually counts down in this game whether you get the button presses right or wrong, only stopping temporarily for short breaks occasionally where the leader of your unit will make a comment about how you are doing or how she feels.
If you manage to fill up the bar all of the way, you will see the word BONUS! flashing on your score bar. This means that you will get the maximum amount of stat increase that you can receive from that one particular lesson.
Visual Lesson[]
Visual Lesson - Click to Enlarge
The visual lesson has lyrics from the current song that you are producing listed on the bottom of the screen, and boxes in different colors floating all around that list different emotions. The objective of this mini game is to match the emotion from the lyrics to the floating boxes.
This game is very simple even if you can't read Japanese, because the boxes that you need to click on always match the color of the box that lists the lyrics on the bottom. If the box at the bottom is yellow, for example, click on the 3 floating yellow boxes by moving the pointer over to it with your analog stick and hit the A button.
Whenever you click on a wrong box, the game will either give you a small portion or zero toward the score bar depending on how many correct boxes you had clicked. The timer will keep going down even as the girls complain. Clicking on all 3 boxes will stop the timer between sections, making it beneficial to get as little incorrect as possible!
If you manage to fill up the bar all of the way, you will see the word BONUS! flashing on your score bar. This means that you will get the maximum amount of stat increase that you can receive from that one particular lesson.