Anatomy reference and ZBrush tutorials were from Marc Brunet and Pinterest (Pinterest is a great site for reference study). For Blender tutorials, I primarily used Skillshare, selecting the most viewed ones (If you just needed the basic knowledge, Blender Guru YouTube tutorials are great, but not exactly for the character creation). Sculpting in blender was self-taught, in ZBrush Marc Brunet tutorials and self exploring. Texturing involved an advanced Substance Painter 3D course from Nexttut and numerous YouTube videos. Clothing design was primarily from Skillshare, Marvelous Designer tutorials, and finally, rigging was learned mainly through YouTube tutorials (Its really hard to find a rigging tutorial for a specific character).
Basically I butchered information from different sources and used it for my specific needs.
My advice if you want to start or improve in 3d art. Take it slow and don't give up when a difficult or even impossible task pops up. Just wait a couple of days and try again.

I hope this information will be useful to you.