Kill Everything That Isn’t an Innocent Human
Seriously, if it moves and you can’t go to jail for it, kill it. Goblins, cyclopes, griffins, harpies, bandits, seagulls, even bunnies. Kill them all. This is particularly useful in the very beginning of the game where you won’t come across too many foes outside of goblins and monsters far too challenging for you.
You can manage to hit level 5 in a relatively short amount of time killing nothing but bunny rabbits while trying to get a feel for the controls. You will also be able to gather resources that you can both use and sell, so there are nothing but benefits from farming literally everything with a heartbeat.
Just remember, stay away from innocent people. Jail can be quite the damper on a great adventure and you’ll be stuck with having to get out. Be a hero and kill some random creatures instead.