>>109599First step is laying out your plan, pick up a document and write down a general idea of what are the strong points you want to focus on in your game, and what would be the best approach to achieve them, if you got a good idea of what genre, visual and engine you want for it mark it down at that step.
Second step is figuring out the progression; how long would the player have to go through the gameplay loop and figure out what would be engaging in it, as well as how to keep the engagement, pace, difficulty, rewards and such.
Third step is writing the characters and plot, depending on what you want to make, this can vary from plain old descriptions of characters and their general activity, up to actual character arcs with a development, want and needs, obstacles they have to go through, and personal progress they have to make, if you want to make something that complex however, write down character traits, personality, good or bad habits, their way of responding to situations, relationship with other characters, fears and goals, just so you have something to fall back to when you need to figure out how X character would react in Y situation.
Once that's done, again with the hypothetical complex story, otherwise skip this step; write a cohesive plotline, you want a start, a finish, and steps to it, usually by going through a process that goes something like 'X was going to do Y, BUT decided to Z, BECAUSE of Z, Y was or was not achieved, then, character decided to A, BUT/BECAUSE OF Z, B happened, character overcame B and THANKS to A decided to C.
It needs bumps and consequences generally, that's how good storytelling goes, if you don't do that usually your story is trash and a series of 'character does A then B, then C, then D' which is probably the worst writing you can muster up.
When you got your laid out plan and writing planned somewhat, it's up to your skills really.
If you don't know how to code, learn to code, if you don't know how to do art, learn to do art, if you don't know how to compose music, learn to compose music, there's no magic trick there, just baby steps, pick a goal that is part of the greater scheme, stick to it, persevere, and you'll get somewhere.
