Well, you can't learn by just someone telling you how to. You must either do everything like the code and art by yourself or hire people to help you with it. Obviously you should hire someone or else it will never get done, unless it is a small mod that changes very little the main purpose of minecraft. I am no mod maker, so don't ask me to help, sorry . With help I am sure that you can make a mod and eventually be able to make a mod with very little help (you will always need someone or the process would be excruciatingly slow). You will need tools to edit art for your mod and other code applications. Try watching YouTube tutorials like Animatrix said. This probably didn't help you much...

Ignore the trolls~

Use youtube for tutorials, but you'll need Minecraft Coder Package and a program called Eclipse.