Which skill should I learn to be successful and make money?

You have two choices

First, you can learn a skill so that you can make money to do the things that you want to do

Secondly, you can learn the skill required to do what you want to do

If you do the first and devote time to making money to do what you want the chances are that you will spend much of the money on things that do not satisfy you and at some point realise you have wasted both time and money

This is why some rich people feel they have wasted their lives earning money for the sake of it and not using their resources to follow their dreams