How do I maximise my potion result in Two Worlds?

Here are a couple links that may help: Alchemy Basics This also has a link to a list of ingredients and what they do. The Ultimate Manual This is a pretty good in general guide to everything in Two Worlds. and Recipes Not a comprehensive list but contains an answer to your question Quoted here:

First off, it's useful to have your Alchemy skill at 10 (there's a trainer in Rovant Village, west of Tharbakin, to get you started), as this derives the most beneficial results in your end products. Second, if you've fooled around with the system at all, it seems to give the best results to use 10 (the maximum allowed to make one potion) items, meaning you're using several of certain of the items. Third, it seems the key is to use more non-mineral items in your formulation (things derived from plants and animals, such as beaver fat or lavender, or even health or mana restoring potions, as filler) than mineral items (such as diamonds or rubies) in order to make permanent potions (and, since the permanent stat-increasing potions are probably most useful, those are the ultimate goal). And, since we want to use ten items to get the best results, that means 4 minerals, and 6 non-minerals (obviously).