In some details the walkthrough (and also the one Drunk Robot posted on Steam) is outdated :
Skills improving:
Charm - tan at the pool - max 30
Knowing - read the red book in Leon's room (buy the book in the grocery store $100) - max 30
Strength - swim in the pool - max 30
Charisma - persuading - hilo mini games (persuade Saul about Nadine's Uniform) max 11
Power - not implemented yet
When playing through the game I noticed :
Charisma
Charisma is increased by persuading persons, e.g.
- persuade Saul to give you more money, (+1)
- persuade Saul to modify Nadine's uniform, (+2)
- persuade Edgar to do a boat trip, (2 x +2)
- persuade Nadine to work at the brothel (2 x +2)
I started with 10 charisma and got another 11 for a total of 21 charisma.
Power
Power is increased by certain repeatable actions, e.g.
- make a girl drunk level 6 and have Leon drunk level 4 or higher get access to the girl's room and use her,
- brothel private lap dance with hand job / blowjob or brothel upstairs.
Max power is 30.
If Leon uses a sunday for the drunken girl action he can repeat it 6-9 times depending on circumstances and can get 6-9 power in a day.
Influence of skills and cash on NPCs
Skills determine how much relation points Leon gets for his actions depending on the npc settings :
Nadine : Charm, Knowing, Bank account (1600)
Sasha : Charisma, Power (400)
Alison : Charm, Strength (400)
Jenny : Charm, Knowing, Bank account (400)
Kevin : Strength, Power, Bank account (400)
Alexandra : Strength, Power, Bank account (3200)
Edgar : Strength, Charisma (800)
Stella : Charm, Charisma, Bank account (400)
Saul : Knowing, Charisma
Gregory : Knowing, Strength, Bank account
(Pablo : Strength, Charisma)
Bank account means that Leon gets more relation points the more cash he has in his pocket which may go up to 40-60 points per action after maxing other stats at 30.
Sasha is the character with the slowest progress since Charisma cannot reach 30 and most players first need to discover how to increase Power.
Lust
Lust for each girl is reset every day to zero.
You can flirt once a day with each girl to get +2 Lust.
Applying sunscreen to Nadine can give +2 Lust for Nadine depending on used dialog options.
Changing Nadine's uniform to clogs, telling her and groping her ass can give +2 Lust for Nadine depending on relation.
Doing the boat trip with Edgar and Alexandra can give +2 Lust for Alexandra depending on used dialog options.
When doing a Date with a (lonely) girl at the village bar, looking at her boobs gives +1 Lust (up to 3 times?).
To max out Lust, combine e.g. Flirt, sunscreen/boat trip and evening date.