I've got two help posts from some great authors that I came across in my internet wanderings. I also have two character based writing tips. I always find good characters, which inner turmoil and motivations, who feel read, are in the best stories.
Look, Do You Want This Or Not - Maggie Stiefvater
Resources on writing a character with mild PTSD - ANC Writing Resources
IN WHICH I CRITIQUE YOUR STORY (THAT I HAVEN’T READ) - terribleminds
Character Motivations - It's a Writer Thing