I believe the most intricate plot won't matter much to readers if they don't care about the characters, especially in a series. So I try to focus hard on making each character, whether villain or hero, have an interesting flaw that readers can relate to.
“I had two family members involved in World War I: two great-uncles. One of them is on a memorial in France. And the other was a trench runner who survived the war. The average life span of a trench runner was 36 hours, but he survived the whole war.”
“I used to work at this store called Music Plus in San Clemente, California, when I was growing up, and then they became Blockbuster Music, and, like, you had to get a haircut to work there, and at the time I had some pretty long hair. So after that policy was imposed, I knew that was going to be my ”