How to make modding programs? [ Starter ]

[I_Bang_Fat_Chicks]

Well ive been on this site for some time now and i appreciate every single person on here who has uploaded all their hard work for us to use and enjoy..
But just out of curiosity id like to know the step by step of making a modding program/save editor.
Why?
Well because honestly.. i think its pretty badass and cool as hell that you can do something as awesome as mod a game and/or system.
Just to have the option to say.. "Well, i dont like how my character looks i think ill change that" or what im sure everybody says "Time to get rich!" Haha
But i really do envy you guys for having the skill and experience to do such things and im sure its not all fun and games though.
And i know that it takes time and lots of it to learn how to make editors but im currently not working anymore but am getting back in school so i have time.
So if anyone has any advice for the future, tips, the to do's and not to do's and the things i need to start my journey of making mods and editors just post away.
Also, id like to thank everyone who takes the time to read this and help.. And hopefully this will be a popular post so that more people like me can learn.
One again, Thanks to everyone for your hard work and support.