Motivation is the easiest thing to find tbh... And honestly, if you can't find the motivation for it, I think writing might not be for you.
Between finding motivation to write and actually writing though, there is a big hurdle to cross... Mainly, procrastination. As well some other stuff like Writer's Block, lack of inspiration, some game that makes you lose track of time and yada yada... But procrastination is like, 10000x stronger than those other things from my experience.
As for how to bypass procrastination... Uhn... It's hard. Here are many different methods that may work to different extents depending on each person, I have tried pretty much all of it myself:
- Making a schedule.
- Desperately needing money and having some way of instantly monetizing your work.
- Talking to a psychologist.
- Taking meds from a psychiatrist.
- Releasing chapters as you finish writing them AND getting comments from readers that are invested in your story (the second part doesn't depend on you, but it's one of the things that helped me the most when I was writing my first novel).
- Getting a boyfriend (I swear it helps, believe me).
- Setting a work environment.
- Staying away from your phone during writing hours.
- Making your writing hours as hours that "You do not need to write, but you will not allow yourself to do anything else... Generally, that will make you write, because it's less boring than do nothing" is a tip I got from the blog of a famous author (forgot their name), though I have never been able to have a strong enough will to follow through with this.
- Blocking your favorite sites/hobbies that make you waste most hours until you actually do your share of writing for the day (This one can actually make you even less productive, mind you, so do this one with caution).
And uhn... That's about all I can think of. At the end of the day, all of those methods will only help you sit down on your chair and open your writing document... But that's it. They'll only help, actually doing it and actually writing it depends on you.
Personally speaking, it took me 5 years of trying to work from home-office until I started getting some results from this... Which is what is allowing me to pay my bills by... Translating.
Writing is my dream job, and I plan to one day substitute the translation for writing, but... I'm still struggling to regularly translate 5 chapters/week, so... I'll have to get steady on that front before I can go back to writing regularly.
So uhn... Good luck. It's pretty hard to overcome procrastination, and while some people have it easier than others, pretty much everyone struggles with it to some extent. Do your best~