Other than maxing your weapon expertise of choice (I played a duel wielding warrior), get Bleed up to level 10.
For non-combat skills I maxed Lockpick as soon as I could, and after getting the battle tower, maxed Mana Efficiency (helpful for awhile, but probably not necessary), mostly so I could summon the creature and still have enough mana left over to heal if I needed to.
I had lots of 'level 1 is good enough' type skills: Mana Leech (put a point in later in the game, when I had plenty to spare), Healing (learned as soon as I could), Evade, Whirlwind and Rush Attack (I had it up to level 4 before reskilling after getting the battle tower). I put 1 point in Potion Efficiency before the battle tower, and maxed it afterwards (which was unnecessary, and I probably wouldn't do so again).
