There are 29 skills in Unreal World. Each is represented by a letter of the alphabet and can be accessed by pressing Alt + the letter.
Skills can be improved with practice, only on a successful use will a skill improve (minimum success chance of any skill is 5%). Intelligence/Willpower don't affect the process, but certain tasks are more 'educational' than others, for example you'll learn more about timbercraft by making logs than you would by chopping firewood.
Also, the lower the skill mastery level is the faster the skill will raise upon succesful usage - so there's a 'learning curve'. It takes far less effort to go from 6% to 7% than from 76% to 77%.
You also want to look for skill training methods
How skill points are assigned at character creation.