My first proper mod was to reduce the amount of water on the desert map, and that grew into adding wheat and a food source which could use the bakery (the now semi-famous Oasis Mod
). This is actually a simple change, but it explained most of the major mechanics so simply that most of my mods are based at least partially on this first mod. I find this is the best way to figure things out - finding a solution to a problem makes you think much more about what you're doing than just reading a tutorial or spamming/nerfing a statistic.
Just because you'll love this idea, why not try making a mod which turns your townies into zombies? You'd need to find the zombie graphics and use them to replace the generic townie graphics, and perhaps alter the stats to be more zombie-like. You could also have some of them be ghosts by using the <alt_graphics> tag, and have your heroes become vampires/skeletons. Of course, you'd have to find new skins for the monsters in the dungeon as well - perhaps nosey knights and zealous slayers (the knight skin, the barbarian skin, townie skins etc)?
This will give you an excellent grasp of the graphics, without having to fiddle around with your own new graphics. You could then try making your map more suitable for a master necromancer - add in vast swathes of barren dirt, lower the number of trees and animals, make raw meat a better food source (what self respecting zombie bothers cooking their meat when they can have it fresh?), give bone walls a roof etc. This may seem like a big and complicated mod, but if you do things one step at a time and check the explanations above the functional script, you should have no problems (plus, we're happy to help if you do have any issues of course).
What's that you're eating? A nice, juicy apple? You weren't supposed to eat that you fool, you were supposed to make it into a pie! - last words recorded words of Francis D'Avre before he went looking for snowcherries, but found a hungry Yeti instead.