Thanks, and those inspirations you listed (Psychonauts and Gorillaz) are already pretty accurate, I guess I'd add One Piece to that list.

As for advice, I'm pretty bad at giving any lol. But I'd recommend looking up a good color palette that really appeals to you, and try to analyze it and figure out how and why it works so well. Back in the day when I was doing a lot more pixel art, I found this one:
https://grafxkid.tumblr.com/post/137439294099/grafxkids-today-land-palette-release
And from there, I was kinda able to slowly figure out what I liked to see, and how to make it myself.

For the actual technical skills, that just comes with time as you grow more and more accustomed to your software of choice (I use FireAlpaca) and learn all of its little tricks and features. I hope this helps a little bit