Skills in the game can be divided into two types: those of the protagonist and those of the Special Workers.
The innkeeper skills include: Oratory, Passion, Deception, Wisdom, and Intimidation. They are trained during conversations, when choosing an answer related to the skill. These answers may have two effects: they increase the level of the skill and affect the protagonist's relation with a given NPC, which in turn affects the dialogues and even the end of the game.
The dialogue window often says what effect a given skill has of succes (for example: an Intimidation-based answer may have a 20% chance of getting a positive result, while Passion may have 90%).
Special Workers Skills
Skills of your special workers include Strength, Dexterity, Intelligence, Charisma, and Endurance. They all can be trained and leveled up when using a special object.*
Strength can be trained on a punching bag or fighting a dummy (this includes Halloween scarecrows).
Darts, which can also be thrown at a dummy, train Dexterity.
Reading books increases Intelligence (it requires an object with books and a place to sit).
Charisma is leveled up when a character is talking to other guests, as well as using a dressing table or writing songs at a desk.
Endurance rises when a character uses a dummy or a punching bag.
*Known bugs: some of the objects may not have among their Trait icons the icon related to the Skill that can be trained using it; instead there will be empty space where the icon should be. However, when hovering the mouse over the icon, a pop-up text will appear, saying what Skill will be trained when using this object.