@Rabbival507
Doing it yourself through work is really the best way. And I mean doing it over and over, and over, for years. You don't necessarily need to share everything you write, it's just for your own benefit. I took part in an online weekly one-hour composition event for a few years, and it was a great opportunity to experiment because if something didn't work, you only spent an hour on it so no matter!
When I first started writing music (10 years ago I think) I wrote quite pop-music kind of chord progressions. Although I improved very gradually over the years to become more and more interesting, there were two pieces of music in particular that were major influences on my style and my harmonic language, which might or might not be of help.
The first of these was Janacek's opera 'The Cunning Little Vixen'. You can find the full opera here - https://www.youtube.com/watch?v=QQhLyG3_HnQ (skip to any random point and you'll find beautiful music) but you can also find a cut-down orchestral suite at https://www.youtube.com/watch?v=a79nSbmy69U which will give you a very good idea of the overall musical language. I played this opera while in my city's youth orchestra, so I got a lot of opportunity to hear the music in action and think about how it worked.
The second was 'Loops II" by Philippe Hurel, a piece I learned for my final undergraduate recital for my bachelor's. https://www.youtube.com/watch?v=m8WtE7uI8a8 is an ok recording. You probably need the score to fully appreciate it, but it really expanded my definition of 'consonance' and I find myself using ideas from it all the time in my music now (like in my 'Tarantella' guitar duet I posted recently).
As to how I wrote these progressions, it was mostly instinctive, so I'm not sure how much I can explain. Bar 87 is a particularly good example of this - while writing I just 'knew' that it had to go to an F# chord. Probably on analysis I might be able to find a specific reason. I'm not saying that F# was the only chord it could go to or that it was even the best chord, but my mind was positively crying out for it to be an F# chord and it just couldn't be anything else at the time. It just flowed naturally in my mind as I was writing it and I didn't have to think about it at all. That's often how I write - through instinct (and also through playing around with music in my head while walking anywhere). Instinct can only come through practice. Keep writing, do silly stuff just for the sake of it and then look back on it afterwards and see if you can figure out what worked and what didn't work, and why.