You'll need something to write with, something to write on, and a willingness to pretend.
Think of a fantasy gaming scenario that appeals to you. Could be anything. Sword and sorcery. Giallo. Romance. Western. Erotica. Cyberpunk. Dystopian pastry chef. Mecha. Anything. Think about the setting, the overall sense of the world, and the possibilities it contains. Write down as much detail as you care to, or maybe you can keep track of it all in your head.
Now, imagine the character you want to play as within that world. Write down as much detail about your character as you care to, or maybe you can keep track of it all in your head.
Here comes the heavy writing part. You write down a scene, and then you give yourself a set of-at minimum-two choices about how your character responds to that scene, and then you choose one of those options as the basis for the next scene which will also end with a set of two or more choices to make. Every three scenes, you must write down an X-Path Scene, which occurs outside the main flow of your player character's existence.
This X-Path Scene must exist as a complete opposite or negation of whatever the overall trend of the main flow happens to be: if your main flow is good, the X-Path is evil; if your main flow is violent, the X-Path is peaceful; if you are victorious and hyper-competent on the main, then you would be a pathetic loser in the X-Path, and vice versa.
You have total discretion, since this is a solo gaming endeavor. You can cheat. You can have the main flow and the X-Path crash into each other. You can play without actually writing anything down. You're free. At least, I like the idea of you being free.
Once you’ve written down an X-Path scene, you return to the choices you wrote down at the end of your third scene, pick one, and when you write your fourth scene you must incorporate some element or some awareness of what's in the X-Path scene. If your character is a psychic, maybe they can perceive this other possible self. If your player character happens to hear a radio it could be a news report describing whatever’s occurring in the X-Path. If your character watches a movie, then the movie could have a scene inspired by the X-Path. Or, your character could just have a memory of a movie or TV show they once saw that's like the happenings of the X-Path. There's some kind of bleed or signaling or influence coming from that X-Path into the main flow of your game. This tantalizing sense of this other self, or impossible self, or self you’ve forgotten, or self you despise, or self you desire that's just out of reach.
Remember, you write down an X-Path Scene after every third main flow scene. Keep this up for as long as you're having fun. Share it with a friend. Or keep it as a secret. Use magnets to display your character's journey upon the refrigerator. Or rip it up and throw it in the trash. At the very least, I suggest re-reading it once, holding onto it for awhile, and maybe looking at it again at a later date. But that's just a suggestion.
If you want, you can incorporate dice rolls to help you decide which choice you make at the end of each main flow scene. For example, if you have two choices, roll a six-sided die, and if you roll a 1, 2, or 3, then you make the first choice you wrote down; 4, 5, or 6 means you go with the second choice you wrote down. If you wrote down six choices, assign each choice a number all its own. This can be fun, but it's also optional.
You can use notebooks, loose sheets of paper, long rolls of butcher paper, napkins, index cards, crayons, pens, pencils, paint, your mobile phone, your computer, voice dictation, whatever you want.
If you don't like writing, or this sounds like more hassle than it is worth to you . . . I totally understand. You are free not to play.
But . . . you may experience a sense of what your life was like if you had played . . . emanating from that X-Path . . .
