I would probably start putting some into constitution, but if you are not getting hurt much then you don't have to worry too much about it. You should get more then enough mana from mana and intelligence equipment bonuses.

If you have or learn level 1 in Sword Expertise or Augment Damage (the starting skills for the male warrior), the next time you save and load the game you will have level 2 in these skills.

Free skills, and spell books you can buy

I ignored the elemental damage skills, due to their low chance to hit (it gets better when maxed, but by that time I didn't really need the extra boost). I found the passive Stun skill quite handy, though.

I maxed Wisdom. It only gives you an extra level by the end of the game, but as a warrior I had plenty of spare skill points anyway.
Wisdom - is it worth the skill points?

I found Survivor's Instinct marginally handy to top of your hit points when you go trade or drop off loot. It isn't fast enough to make a noticeable difference during battle, though. I put a couple skill points in to test it out half way through the game, or so, and then maxed it when I got to the wastelands, trying to use up some skill points.