nuekboi said:
Set yourself goals as to what you want the current version to be like. Too many people try to add a million features without planning how they're going to get it done. Start off by just getting a working version of your mod done, with new factions, a map, and the troops and basic cosmetic things.
Then work your way around the module system, looking for scripts or bits of code you might want to change to fit your setting, like the speed people travel in different situations or the type of troops you can get. This takes the longest but you'll learn a lot, and eventually be able to create your own scripts and implement them on a whim.
Stuff like dialogue, faction backgrounds and lord names can be really difficult for some people, and there's a lot (several thousand words) to change. If that's the case, you'll want to gradually plan what the factions are like while you're making the rest of your mod (not just a vague military descvription like "has good spearmen", but a proper culture that makes sense in your universe). The best mod universes are the ones that fit in with the game's mechanics. So say you want to make a mod focused on horse archer combat, it'll make sense to have nomadic factions on a large, flattish map with few trees, possibly giving lords banners with horses or deer on them, or even a hunting mechanic. Some of the factions might have lots of semi-independent lords with small armies, while others might own a few walled cities and get involved in trade. Stuff like that really helps immersion and makes your mod stand out.
Anyway, don't let me discourage you. Good luck.
