Below is a walkthrough for the Raise Some Skill Levels task in Rune Factory 5.
Client: Ryker
Objective: Level a skill to 20
Reward(s): 3000G
After completing most of the tutorial tasks, the one will show up on the Task Board. After accepting it, Ryker will task your character with leveling a skill up to 2o. Chances are you probably will have this one done before receiving the task. If not, we found the two easiest ways to level up were mining and walking. Walking levels up naturally as you play the game and mining gets leveled up by using a hammer on rocks. Return to the Task Board after raising a skill to 20 in order to complete the task.