I need help with modding.

I am a complete and utter noob at making a mod. The only things I know how to do are print, and comments. I want to make a mod that improves the sky texture of minecraft. I look on youtube but all the tutorials I find are for making items like swords and pickaxes. I need to find out how to make better textures that can change at certain times(night, day, sunset, sunrise) and I need to have it have options to toggle the features on and off in the options menu. Please help!