All credit goes to sturmtiger on GameFAQs for the following information.

What to do with gems and jewellery with no enchantments?
Sell them!

Weapon Effectivness:
Bladed weapons inflict half damage to undead enemies while blunt weapons cause full damage upon the undead.

Universal Weapon Modifiers:

• Fine = Increases max\min damage by 150 %.
  
• Masterwork = Increases max\min damage by 200 %.
  
• Shock = Adds +1 min, +24 max lightning damage, added after every blow.
  
• Frost = Adds +1 min, +12 max ice damage, added after every blow. Has a chance of freezing the enemy.
  
• Flaming = Adds +1 min, +6 max fire damage, added after every blow. Has a chance of setting the enemy on fire.
  
• Shocking Burst = Adds +1 min, +24 max lightning damage, added after every blow. On a critical hit, adds +1 min, +40 max lightning damage.
  
• Icy Burst = Adds +1 min, +12 max ice damage, added after every blow. Adds +1 min, +20 ice damage on a critical hit, and has a high chance of freezing the enemy.
  
• Flaming Burst = Adds +1 min, +6 max fire damage, added after every blow. Adds +1 min, +10 max fire damage on a critical hit. Has a high chance of setting the enemy on fire on a critical hit for two seconds.
  
• Keen = Increases the chance of a critical hit. Reportedly around a 1/6 of a chance of critical damage per hit.
  
• Wounding = Inflicts the enemy with constant damage for four ticks. There is a random chance of the damage inflicted per tick being from 1-5, and the damage stays as that for the duration of the wound. Lasts for two seconds.
  
• Jewelled = Doubles the price of the item. The price is doubled after all other price modifiers are added.
  
• of Defence +(x) = Adds (x) to min\max damage. (x) never increases above 5. Adds an AC bonus, based on the value of (x). If (x) is 1 or 2, AC increases by one, if it is 3 or 4, AC increases by 2, if (x) is 5, AC increases by 3.
  
• of Speed +(x) = Adds (x) to min\max damage. (x) never increases above 5. Adds an attack speed bonus, based on the value of (x). The attack is faster if (x) is higher.
  
• +(x) = Adds (x) to min\max damage. (x) never increases above 5.

Suited for intermediate players, Vahn the Arcane Archer gets the ability to use every weapon in the game but is most proficient with, you guessed it, the bow.

Recommended Stats (in order of priority):

• Dexterity
  
• Strength

Recommended Jewellery:

• 1x Amulet of Dexterity
  
• 1x Ring of Strength
  
  -or-
  
  
• 1x Ring of Dexterity
  
• 1x Amulet of Strength

When Levelling:

• Put all points into Dexterity

Recommended Abilities (in order of priority):

• Shock Arrows
  
• Hail of Arrows
  
• Repulsion (Just one point)
  
• Ice Arrows

Exploding arrows can be fun but dangerous, fire arrows are weak.

Recommended Passive Skills (in order of priority):

• Death Blow
  
• Improved Critical
  
• Enchant Arrows
  
• Arcane Quiver
  
• Willpower
  
• Meditation (2-3 points max
  
• Combat Reflexes (1-2 points max)
  
• Deflect Missiles (1-2 points max)

Suited for beginners, Kromlech can use all equipment in the game and can wear the heaviest of armour. (However, in the late game, armour is pretty useless due to how BGDA calculates damage reduction rolls.)

There are two primary ways to build Kromleck, using one-handed weapons with a shield or using two-handed weapons. Below I'll list which skills are best suited for each build.

Recommended Stats (in order of priority):

• Strength

Recommended Jewellery:

• 1x Amulet of Strength
  
• 1x Ring of Strength

When Levelling:

• Put all points into Strength

For one-handed weapons and shield builds:

Recommended Abilities (in order of priority):

• Unfortunately, there aren't any *must get* abilities for this build.

Recommended Passive Skills (in order of priority):

• Combat Reflexes
  
• Sword and Fist
  
• Improved Critical
  
• Death Blow

Once the above are maxed, then spend points in:

• Dodge
  
• Intestinal Fortitude
  
• Shield Expert
  
• Endurance

For two-handed weapons builds:

Recommended Abilities (in order of priority):

• Whirlwind Attack (Get this ASAP!)
  
• Clangeddin's Fist (For Hammer Users)

Recommended Passive Skills (in order of priority):

• Improved Block
  
• Combat Reflexes
  
• Sword and Fist
  
• Improved Critical
  
• Death Blow

Once the above are maxed, then spend points in:

• Dodge
  
• Intestinal Fortitude
  
• Meditation
  
• Willpower

Suited for experienced players, Adrianna really shines in the late game with powerful spells and a decent fighter to boot! She can equip all armours and all but the heaviest of weapons. It is recommended to use a sword and shield.

Recommended Stats (in order of priority):

• Constitution
  
• Intelligence

Recommended Jewellery:

• 1x Amulet of Strength
  
• 1x Ring of Strength/Intelligence
  
  When Levelling:
  
  • Focus on Constitution
    
  • Put the odd point into Intelligence
  
  Recommended Abilities (in order of priority):
  **This is more down to personal preference, but here's what I gravitate towards:**
  
  • Magic Missile
    
  • Lightning Bolt
    
  • Ball Lightning
    
  • Meteor Swarm
    
  • Mordenkainen's Sword
    
  • Fire Shield
  
  Recommended Passive Skills (in order of priority):
  
  • Intestinal Fortitude
    
  • Willpower (3 points max)
    
  • Meditation
    
  • Accuracy
    
  • Targeting

Hope this guide has helped you. As mentioned, this was mostly just me reformatting information I found online for ease-of-use on Steam.

If you like this game, please consider dropping me a follow me on Twitch[twitch.tv]where you can catch me playing other games in the Baldur's Gate series and similar games like Divinity: Original Sin.

You can also check out my other guides here:
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=186442320
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2311301481

Thank you for reading!