TL;DR: Skip to the bottom and read the articles.
Well, every (well, all viable ones, but every one should) method has a purpose, a reasoning behind the why that method is to be considered as viable, or the reasoning behind the steps. This could be anything, like reducing blind spots and edges involved in eo during petrus (like APB), or exploiting cube symmetries to cover more possible cube states and lead to more efficient solutions (Mehta), or improving the move count of CFOP while retaining its TPS f2l spam (ZB). It could even be an amazing substep/keystep ideas for a Meta method (article linked at the bottom). Now, those examples might not be entirely accurate, but it’s sorta right (I hope). Now, there isn’t more than one way to make a method, but there are good ways that have been tested by the best in the method development field. I suggest you read
https://www.speedsolving.com/threads/on-key-steps-and-meta-methods.86039/
and
Metohd development guide for Rubik's Cube and other puzzles.
www.cubingmethods.com
which are both by two absolute GOATs in method development. Take some inspiration and advice from these two, and you are bound to conquer the world (figuratively speaking, of course). Also, make sure to be inspired and take advice from others in the community on the
https://www.speedsolving.com/threads/the-new-method-substep-concept-idea-thread.40975/