Now is as good a time as any to return to Broken Valley and clear up any remaining quests or business there, as they will be unavailable once you take the battle tower.
You can also go through the beginning of the fjords. That can give you a couple levels relatively quickly. There is a winding path down a mountain there, and I went from just hitting level 16 at the top to 17 at the bottom (level 18 opponents). Clearing out across the next beach and then swimming over to another stretch of beach brought me up to level 18.
Have you tried using your creature or a summon as a distraction? I found the creature more helpful as a ranger (Fireball 2) than warrior (Rush Attack / Fatality 6), and much better as a mage (Magic Missile / Magic Blast). Depending on the situation and distribution of opponents your creature can make a pretty good shield while you use a bow or magic. At level 22 I took out a level 27 beholder mage using a bow to do damage while my creature lasted, and then rush attacking to get as high a DPS as I could to finish him off before he could hit me a couple times and finish me off.
