Modding C&C Tiberian Sun for PC

[Hero in a half shell]

I thought I'd dust off my old Command and Conquer games, but really would love to enhance the my Tiberian Sun with mods.

Can anyone give any advice of essentials I need to know before jumping into the modding with both feet (tips on how to mod it, the best mods available etc.)

Here's some nostalgia to rock out to as thanks:

 

[SmugFrog]

If I remember correctly there was usually a file called rules.ini for the old C&C games. You tweak that thing to everything you want (mostly), and make some amazing things happen.