What Kind of Underwear does your Character Wear?
No—this is not the inquiring of a pervert. Really. The point behind the question is just how well do you know your character?
Listen, a character doesn’t become the metaphysical flesh and blood without a lot of your real sweat and tears. You might be the type who doesn’t write the first line without immediately putting together a detailed outline—you might know every twist and turn your character is going to make before actually sitting down to write the novel/story, but that isn’t enough.
What the heck do the undies of my character have to do with you? perhaps you ask, a hand on hip and threat in your eye. Well… It doesn’t. Not really. It doesn’t mean much to me but it is instrumental to YOU. OK—so you say there’s not a need for even the word underwear to make it into your novel, let alone a detailed description (too bad…), but that’s not the point. The reason why the question is posed is to remind you how in depth you need to go whether in your head or on paper with your character sketch. Knowing the type of undies your character wears—if any, the things they like to drink, the way they take their coffee, choice of shoes, etc., etc., etc. are the building blocks to the skeletal frame of the character(s) you are crafting. You, as their creator, should know as much as you can about them—this is what will allow you to effortlessly write the details that will make the reader frown, drawing close to the page, forgetting they’re reading a ‘story’ and instead feel they are getting a glimpse into someone’s life.
You don’t need to spend hours on this, nor do you have to formally write it all down (though that helps) and, like any person we know, the things you discover about your character will not come to you all at once. The important bit is to keep your eyes open—look. That silly little difficulty you had standing in the grocery isle trying to decide between whole grain or bleached white bread… Use it as a learning opportunity; ask what would your character do?