The Modmaker's Guide To The Galaxy, created by "Fingers" of Digital Eel, is a source of incredibly useful information on modding, including explanations of what various commands and flags do, walk-throughs of how to create your own races and mods, etc.
It is organized into the following sections:
Source: Modmaker's Guide
The Basics - How to set up the folders etc.
Creating a Starship - Covers ship graphics and game data. Download included.
Particle Effects - Describes the Weird Worlds particle system.
Creating an Alien Race - Create a new enemy race. Download included.
The Quest System - A wellspring of arcane wisdom.
Engine Limitations - List of various hardcoded numbers.
Changes in WW 1.2 upgrade - Effects of the new version on mods.
There are parts of the Modmaker's Guide To The Galaxy that are confusing. As an example, Conditions such as preenc and homeworld leave out valuable information about their actual limitations and exactly when and how they trigger. Many of these subtle nuances have been revealed by other modders via trial and error. Hence the need for this wiki to compile and comment on things that are counter-intuitive, so that future modders won't have to learn the hard way.