You can make the DK as powerful or as weak as you wish, and it will not effect the end of the game, just your progress up to that point. However, you do eventually get separated, so it would probably be better to use the DK's skill points if you want to learn any summoning doll upgrades (which can not be unlearned). If you are not planning to try the after game BF it will not make that much of a difference, though. Similarly, you may want to favour your hero with any found permanent potions, etc.
Off the top of my head, the main forum topics discussing strategy have been with
Killing Fergus or several on defeating the shaman. I don't recall any totally new topics since the latest patch was released.
The strategy guide does contain tips on strategy and skills, but not as a separate section. Throughout the guide there are tips in difficult areas or with hard opponents, which are usually useful in general. The math appendix contains information that would be useful planning a strategy, but not gameplay tips.
You can not sharpen bows. That shouldn't be a problem, however. I played with normal arrows almost the entire game. At first I was saving up special arrows in case I needed them later for tough opponents, then I was curious how far I could go without using them. There were two instances when my archer started to not pulling her own weight dealing out damage, but I just visited the BF a few times to find a better crossbow. Playing again, I'd stick with bows, switch to power arrows a lot sooner, and of the arrow types, probably just keep normal, power and splitting arrows. Splitting arrows are great for groups of weaker opponents at close to moderate range, especially if you equip the act 1 skeleton doll with a crossbow and have 2 archers using them (I only used a summoning doll to fight a couple times). For strong or single opponents you would have to be pretty close to get best effect from splitting arrows, so it would be better to switch to power arrows. Also, I would think they could be dangerous to use if there are any friendly creatures or NPCs in the area (I only used splitting arrows for one fight).
Since the BF merchants' inventories reset each time you enter the BF, if you have a choice of what to steal it might be better to get the most expensive thing you can and trade it for arrows. I think what you can pickpocket is determined by the level of the skill, but never used it myself.
I had my hero using a melee weapon for most of act 1, switching to a bow/crossbow full time after reaching the citadel. Before that the skeletons were better dealt with using crushing damage. I had lots of arrows, and plenty of loot to trade for more, if I were so inclined.
