If you are a crafter (hand), then making things will increase the level. For example, repairing my weapon as a goldsmith gave me 58 points. Similar scenario with land crafts... you'll level up that job as you do it.
This will be separate from your physical level where you need exp out in the fields is a war discipline.
Refreshed ¦ Reborn
Shori Ohrensztein ¦ Ragnarok ¦ ACN
Reebie Baramnesra ¦ Midgardsomr ¦ MRD