EDIT: I realized the original math resulted in lower scores than I expected, so I made a significant tweak to the skills earned per level. I also removed the Perform skill and replaced it with Craft.
At first level, put 6 points in Abilities. One can be lowered to -1 to put an extra point in another ability. 0 is average, 4 is maximum.
Strength (Str) – musclepower, fitness, health
Dexterity (Dex)- agility, accuracy, speed
Intelligence (Int) – mental ability, memory, creativity
Charisma (Cha) – force of personality, leadership, willpower
At first level, put 2 points in Primary skills.
Fighting – combat skill, offense and defense
Subterfuge – stealth, sneaking, dirty tricks and thievery
Knowledge – science, magic, history and lore
Social – understanding and dealing with people, art, emotions and intuition
At first level, put 2 points in Secondary Skills.
Athletics – jumping, climbing, swimming, running
Survival – wilderness skills like tracking, hunting, finding shelter
Stealing – picking pockets, sleight of hand
Tinkering – disarming traps, opening locks, building traps and machines
Search – finding or noticing hidden or inobvious things
Healing – treating wounds, poisoning or disease with bandages and medicine
Persuasion – making other people believe lies, including disguises, bluffs, misdirection and salesmanship. Can be used for artistic performances.
Craft – building, fixing, or appraising manufactured goods.
When a character gains a level, they get 2 more points in a Primary skill, and 2 more points in a secondary skill. No skill can ever have more points than the character’s level +1.
Background skills: you can allow each character to have a background career, such as Blacksmith or Sailor, which functions as a level 1 skill. The player can add points to it when increasing their level as if it was a Secondary skill.
Non-listed skill: a character can have a Secondary Skill not on the list, if it is not covered by any existing skill. The DM must approve the skill.
High skill option: if you prefer characters to always have some basic level of skill, starting at 3rd level raise all skills with no points by 1 point, and do so again every odd level.
Magic: if using this without Legendary Magic, use Knowledge+Intelligence for arcane (wizard) spells, and Social+Charisma for divine (cleric) spells.