Always choose the "Rest" option when available instead of other dialog options.
Easy "Scientist End Unlocked!" achievement
Have a high rating at the end of the game. To check your progress, pause game play and check the screen with the knowledge and energy bars. Invest all days into studying; and sleeping when the energy bar is low. Visit Kouiji and Youiji or use Gossip a few times per month. The responses in the dialogs will not matter.