Board Thread:General Mod Discussion/@comment-89.102.156.212-20151213135750/@comment-27723099-20151213142104

This is a very broad question. Some general steps:
 * 1) Get an IDE of your choice (recommended is Eclipse)
 * 2) Learn Java programming
 * 3) Get the Forge API and learn how to use it
 * 4) Write your mod