Leveling up cards takes the form of Lessons (レッスン). Lessons use other cards owned by the player in their inventory to increase the experience of another card. Lessons should be prioritized for higher card types such as R, HR, or SR.
Lessons increase the base attack and defense power for individual cards. They require both cards and money. As a general rule, the higher the type of the card, the greater experience that the lesson generates. The higher the level of the card taking the lesson, the more experience that card needs to increase its level.
Levels increase for every 100% experience the card obtains. Lessons consume lower level and lower rank cards, such as N or HN, to increase the level of higher cards. HN cards give more experience than N cards, R cards give more experience than HN cards, etc.The first step in lessons is to choose the card receiving the lesson, the base card (ベースカード). You can change the base card by clicking on the button ベースカードを変更する. The base card will level up in accordance to the cards used in the lesson.
Most cards in Million Live have skills (スキル), which alter parameters in audition battles and festivals. Most commonly, these skills increase the AP or DP of cards in your deck, or decrease the AP or DP of a rival's deck.
It is possible to level up skills by using the gold Otonashi Kotori card, whose skill is skill level up. You can also increase the level of skills by merging cards with a copy of themselves. Skills can be increased to a maximum of level 20. The level of a skill determines how much AP or DP it increases or decreases.
Skills change the AP or DP of the entire deck, of a certain type of card (Vocal, Dance, Visual), of themselves, or of cards of a certain group of idols (such as adults, idols whose birthdays are in winter, etc). Make sure to check out the skills of the cards in your deck to strategically win in audition battles.
Certain SR cards (and, for invite cards, HR) have a second, third, or forth form, which can only be obtained by "awakening" that card. Any card that has a music note holder in the bottom left can be awakened, with the number of music notes determining how many forms the card has. Cards can be awakened after they have reached their maximum level. Obtaining the next form of that card then requires filling the "awakening" meter.
The fastest way to awaken a card is to use another copy of that card in a lesson. The card will merge with its copy to fill the awakening bar completely and open its second form. When a card changes its form, it is reverted back to level 1. If a card has more than two forms, it must be awakened each time, and it still must be fused with the same type of card--a card in its second form must be fused with another of the same card in its second form to awaken it a second time.
It is possible to awaken a card without the use of the same type of card, but filling the bar takes much longer and is vastly inadvisable to obtaining a second type of that card.