There are strong incentives to max skills as quickly as possible, particularly the level 5 perks (e.g., Cooking: being able to eat ruined food). Some quick ways to spam leveling are:
Carcass Harvesting/Cooking: stone/snare rabbits and harvest 0.1kg of meat at a time (by cancelling harvesting mid-action with "Esc"), Fire Starting: amass Sticks and Torches and spam Campfires, Mending: produce several extra Rabbitskin Mitts/Hats and leave them on the ground (outside, for faster decay) and repair them (1 Cured Gut, 1 Cured Rabbit Hide) and to save Sewing Kit condition use Fishing Tackle (don't use it to 0% condition or they'll break, and can't be used for Fishing).