This is a library of most useful tutorials for Mount and Blade Warband. You can use them to make your modifications, you can learn what tools you need, and where to find them.
As Paradigm Worlds Dev I can say from my experience that there is nothing better than Talewords Forum. All questions have been asked, and in most cases answers have been answered. Don't expect that people there will give you anything on plate. They will help you, giving advice, they will tell where to look, but they will not write mod for you.
Personally, I got a lot of help, however that was on Polish TW forum. It was my first day, I wanted to implement 'Cannibalism mod' from polish site and I just installed python and compiled native for the first time. I downloaded mod and been walled in that very same moment. So I asked some stupid question and then, Garedyr (he is in code credits in all PW editions) wrote me a lecture about modding, variables and general basics. 1,5 A4 I would say. But it clarified perfectly everything, and it was amazing introduction to Warband modding. It was very kind, I was shocked then how helpful might be people. I had a few times a luck, people almost wrote a code for me, but such stories do not happen every day. I still remember nick of each one of them.
Four Elements of Modding
Divide modding into sections:
GRAPHICS - that means handling pictures, UI, mapmaking, also 3D objects
AUDIO - all music and sounds, sfx like gunshots, footsteps, etc
CODING - everything that is not GRAPHICS and AUDIO, usually writing in Python-based-Warband code.
They are all covered in tutorials below. Do note, that I did not mention DESIGN. World creation, ideas, philosophy, stats etc. Soon, I will post more articles, covering design too, but better keep these separate.
This is list of tutorials and useful links introducing to Warband modding. They mostly cover mechanics, coding, practical and useful things:
The Ultimate Introduction to Modding by Lumos - Best starter/beginner article
The Forge - Center Base of Modding for Mount and Blade Warband - This is where you begin, and come back for more.
Documentation & Tutorials - This is first place where you should look next. Amazing amount of tutorials, that can inspire you further. No matter if you want create new village, or a companion, or design a banner or add a first weapon - there are tutorials for that.
HINT: I was doing tutorials from this site one by one, and most of them implemented into Warband. This is how you learn. You do tutorials, until you feel that you understand what is written there. Then you do more, and change small things like you add 2 companions instead of one, but second one you try to do without checking too much tutorial. Don't worry this isn't exam, you fail, go for next. Tomorrow you will come back to the part you failed, and this time you are gonna do it. I failed so many times, I couldn't add new factions for FIVE years, and just like that a couple months ago I made it.
HINT: Always choose most interesting things, they will keep you curious for more. Choose tutorials, that you feel, that might be a little bit harder or too complex, challenge yourself. At the end you will see - that wasn't that hard after all, but satisfaction is better.
Guide of Modders - this... this is like a luxury yacht on the ocean of modding. Clear categorization of any possible interesting code, idea for Warband. Also site with another pack of useful links and faq.
Open Source Resources - 'Community-made items, sounds, textures, scenes, and more, open to use in modding M&B.' as TW description says.
HINT: Check Paradigm Worlds DOWNLOAD section for more assets like code, graphic, sounds, and sfx. They will be updated from time to time with new models, textures, etc.
Modding Q&A [For Quick Questions and Answers] - brilliant thread for modding. It is famous, because many Warband improvements made by modders was result of discussions and theorizing ideas. You can learn a lot by studying it, however you will probably never be able to read it all. Currently thread counts 1574 pages. Luckily links to most important elements are already in links based in Tutorials&Doc section. Still handy place to ask or share idea.