Your question is way too general, so I just list down everything:
Combat skill: increase physical attack, intimidation
Scoutcraft: stealth, speed and scavenging for food (at least 20 points of this please, this game is hard)
Wisdom: talk options are more affective, better trade money, more magic attack and scavenging for herb.
Survival: magic defense, avoid ambush and increase trap attack, also effect cooking skill (useful if you want bomb) (at least 15 of this, to avoid ambush)
Constitution: carry weight, HP and Stamina, also buff your sex attack (you literally can rape a man, or normal size monster to their death)
There's a post about skill perk somewhere in here, read it. But the in-game explanation is very clear, read it first.