The walkthrough was written using version 1.45 and the tactical difficulty level. If you use a different difficulty setting, only the challenge of the battles should change.
As of version 1.45 of the game, the "lockpick" skill does not work. So don't invest any skill points into it.
Your luck rating is the average of your character's luck attribute and the deathknight's luck attribute. So it doesn't matter which character you have open chests.
When you find potions that permanently improve attributes, you should let your character (and not the deathknight) drink them.
Holy water can be used to create permanent improvement potions (in conjunction with the "alchemy / extraction" skill). So if you ever see holy water for sale, you should definitely buy it.
Although there is a reputation score in the game, your reputation doesn't make any difference.
Most wizard spells appear to be a waste of time. If you want to be a spellcaster you should concentrate on the shaman spells "hammer" and "lightning storm."
When you find unique or set items, you won't be able to sell them until the following act. Also, set items are broken. You won't gain any benefit from wearing multiple items in a set.
When you "learn" a skill from a teacher or skillbook, that only changes the maximum number of points you can put into it. To actually use a skill you'll have to allocate points to it.
If you're reasonably thorough about killing creatures and completing quests, you'll end the game around level 35.