The levels of enemies can be seen by the color of their name above their head. Yellow is your level, orange is two levels above you, and red is four. Simply venture to unknown areas using your map () to find a red-tagged enemy. To make the fight simple, save a Reckoning ability with which to kill him. The damage from your attacks will help kill any surrounding creatures and easily help you dispatch the mob.
If you leave the starting zone for the zone to the southeast (Haxhi) you should be able to find a thresh that's easy to kill, especially with DLC armor and weapons, and a saved Reckoning. Alternatively, load up the Autosave that the game creates just after the tutorial and head to Gorhart. Commit a crime and agree to jail, then escape and (with a Reckoning), attack and kill either the other prisoner. Open his cell with the switch near the chest that your equipment is in.