How I make my character designs BETTER

How do you refine your character ideas after selecting one from the concept thumbnails?
CSP layer outline button at 9:20: https://youtu.be/TZ9jgwI7rbo

Full playlist of the whole splash art process:

Streamed on https://twitch.tv/pikat
Edited by @SkysagiOP

0:00 Intro
1:30 Sketch
5:58 Lineart
7:00 Design
14:23 Redesign

BGM:
Embrace by TECHNOTRAIN https://dova-s.jp/en/bgm/detail/23159
Night Shift by しんさんわーくす https://dova-s.jp/en/creator/detail/116
Relaxing time with tea by alaki paca https://dova-s.jp/en/creator/detail/44
Last Call Martini by MFP【Marron Fields Production】https://dova-s.jp/en/creator/detail/188
Sunset Echoes by MFP【Marron Fields Production】
Scenery Once Saw by MFP【Marron Fields Production】
Spring’s Silent Bloom by MFP【Marron Fields Production】