Unsurprisingly, Fernet should always go for star norma unless she manages to attain many wins through bizarre circumstances. While it is not impossible, it is highly unlikely for players to get wins with her. Generally, Fernet breezes through collecting and protecting her stars thanks to her stats. Consequently, opponents often ignore her in the early game and wait until the late game to try to KO her. Fernet should focus on Draw and Bonus panels to both ensure more stars for norma, and maintain an appropriate supply of cards to heal and protect her in the late game.
As Fernet is not card reliant, Gift Exchange is highly advised to remove card from other players that will either let them earn more stars than Fernet or get through her solid defensive stats. Flamethrower can also be used, but is less reliable.
Play of the Gods can draw helpful event cards such as Gift Exchange and Dinner. However, it can also draw Fernet's Hyper which will damage her if another player uses it so if you choose to deck this card, try to keep your Hyper out of your hand.
Oh My Friend can summon the Boss which other players are more likely to die to, however it's recommended you attempt to use it though Play of the Gods. Similarly, Pet Snacks buffs Encounter panel enemies.
Draw and 
Bonus panels to both ensure more stars for norma, and maintain an appropriate supply of cards to heal and protect her in the late game.
Gift Exchange is highly advised to remove card from other players that will either let them earn more stars than Fernet or get through her solid defensive stats. 
Flamethrower can also be used, but is less reliable.
Dinner, 
Pudding, and 
Saki's Cookie can help Fernet survive longer.
Play of the Gods can draw helpful event cards such as 
Oh My Friend can summon the 
Boss which other players are more likely to die to, however it's recommended you attempt to use it though 
Pet Snacks buffs 
Encounter panel enemies.
Dark Side of Business can bypass Fernet's DEF and directly take her stars.
Heat 300% and 
Poppoformation are also able to bypass Fernet's high DEF.