
Start with something small! Make One-Shots whether they’re 100 words or a 100,00 words. A simple one chapter One-Shot is a great starting point! Just keep doing those to get yourself into a groove, and eventually you can start writing two chapter fics, then three chapter fics, then ten chapter fics, and so on! Think of it like building muscles at the gym.
seconding this!! starting with something big can be overwhelming. even if you want the first thing you publish to be big, it's still helpful to break it down into smaller steps and think of it that way. definitely recommend trying to build a reliable writing habit if you can—whether it's writing daily or every other day, picking something you can stick to and then sticking to it helps
hell i know some people who they pick out one day if the week and say i'm just gonna write a buncha shit for hours. other people they're squeezing shit out if/when they're just standing around bored going about their daily activities. so besides habit i think it can also just be about making writing fit into your schedule as much as possible regardless, and making it easily accessible as well
set deadlines about it, privately with yourself or publicly to friends or even to your audience...that can increase pressure and motivate you to try to follow through. if it's causing you to freeze up instead though then rather than do this it can be helpful to body double, as in, write alongside other writers like. live in person or online
there's a great site called wordsprints.org where you can just write in your own for a certain amount of time or write alongside people you invite to the session, you can all see the average word count amongst all of you, as well as the total overall word count (and your own individual stats ofc). it helps if you're competitive, i know i end up wanting to keep up with or go beyond the average LOL