I suck at consciously putting characters together. They kind of...coalesce...out of my writing. I don't think that's a very useful professional super power, and so this article helps character-deficient folks like myself:
Creating characters that evoke empathy in the reader can be challenging, but these five methods will ensure that your efforts are successful. And keep in mind that empathetic characters don’t always have to be likable.
It's not a long article, but it provides some structure around crafting solid characters, so check it out here: http://writersrelief.com/blog/2014/05/write-characters-people-care-about/