The procedure for creating a wand is simple. The creator simply casts the appropriate spell on a bone wand in the creator's inventory. The only components you need are a bone wand and a sufficent amount of gold to cover the cost of creation; no gems or essences or any other reagants are required. However, there are some limitations. First, only spells of 4th or level or less can be used to create a wand. Secondly, creating the wand is not free. The creation process costs gold. The cost to craft a wand in NWN2 is equal to Wand Level * Spell Level * 750 gp. Costs for Level 0 spells are half of the cost for Level 1 spells. For example, a wand of Bulls Strength would cost 22,500 gp. Bull's Strength is a level 2 spell, but the wand allows the spell to be cast at 15th level. So the cost is 15 * 2 * 750 = 22,500 gp. Costs for wands can be as little a 375 gp all the way up to 60,000 gp.
You can create a scroll of any spell that you know simply by having the creator cast a spell on a blank scroll in the caster's inventory. Any arcane or divine spell of any level may be placed on a scroll, however Warlock invocations cannot be used. Scribing a scroll costs gold pieces based on the relative power of the spell. The cost to craft a wand in NWN2 is equal to Scroll Level * Spell Level * 50 gp. (Note: This feat remains bugged thru v1.06 and does not function properly, as several scrolls can not be scribed successfully.)
Potions can be created simply by casting the appropriate spell on an empty potion bottle in your inventory. The spell being cast must be a beneficial spell of 3rd level or less which targets a single individual. Warlock invocations cannot be used in the creation of potions. As with Scrolls and Wands, the cost in based on the level of the spell being cast and the subsequent strength of the potion, and can vary from hundred of gp to several thousand. The cost to brew a potion in NWN2 is equal to potion Level * Spell Level * 25 gp. (Note: This feat remains bugged thru v1.06 and does not function properly, often creating potions which appear to be labeled properly but apply the wrong spell effect.)