Creating a custom item - help an aspiring modder?

Let me start by saying that Baldur's Gate 1 & 2 are my most treasured games in my vast collection. In my opinion there isn't really another RPG that competes - at least not well enough to hold my interest like these.

Given that fact, I have decided I would like to start trying to create some custom items for BG:EE. I have read a couple of beginner guides on this subject with using EE Keeper & Near Infinity. I found the guides (that I have read) to be a tad bit lacking in detail. Can someone point me to a detailed outline of what the different global effects, attributes and abilities do in Near Infinity. Is there another modding utility that I should learn for IE modding? I would like to create a dagger that causes permanent blindness on successful hit as my first mod.

Thanks in advance!