Whether for your personal blog or an epic novel, there will be many different characters that will run through the tales you wish to tell. For the most part, these characters will only need a description and a name, but the major players must be given life - they need reasons for the decisions they make. This is where the 'character sketch' comes into play.
The Art of the Character Sketch

Where To Begin
If you’ve never written a character sketch before, I suggest that you take a page from the myriad of role playing games found in gaming stores and on-line. For one, this means that you get to play some video games - yay! The other advantage is that some of these character templates will force you to conform to a layout. Whether you start with the character’s appearance or their abilities, they can help guide you to creating the outline that you’ll need to build their history and explain how they gained those abilities. I don’t mean to suggest that everyone needs to have superpowers; I’m referring to things like deductive reasoning skills, athleticism and knowledge bases. (Have fun with this part - I always do!)
How Did I Get Here?
Where do I fit into this story? This is a simple question that all of my characters ask me. The only way to answer this question is to place yourself in that person’s thoughts and begin telling yourself their back story. CAUTION: This may lead to a temporary multiple personality disorder... but if you’re writing a story, it’s bound to happen eventually.
Every story has a beginning, but only after you build your characters’ history will you truly know where that beginning is. If your main character has been haunted by a childhood trauma throughout their entire life, then that event could very well be your beginning whether you want it to or not. The question then becomes whether or not you want to divulge that information to your readers, or to keep them wondering. Just remember that your readers are going to ask questions that you may never have thought of; if they don’t get an answer, they may not follow you through your journey as an author.
The Meaning Behind The Name
Choosing a name for your characters can be a daunting task. Not only must a name catch the reader’s attention, the character must suit what you’ve chosen for them. A lot of this is based in societal norms and stereotypes, but take advantage of this. For example, the statement, “Look, I ain't in this for your revolution, and I'm not in it for you, princess. I expect to be well paid. I'm in it for the money," wouldn’t have as much impact if it had been spoken by a man named ‘Jon Crowd’ (Thank you, George Lucas for allowing me to quote Star Wars). A character’s name must have meaning. This is why some authors choose not to name their characters until after they have finished their character sketch.

Quick Reference Sketches
If you’re like me and the best portrait that you can muster is a stick man with a cowboy hat, you may need to resort to other means of visual reference. While I was working on my first novel I turned the walls of my office into a tabloid magazine. I wrote my character sketches and searched on line for photographs that matched my creations. These weren’t necessarily actors, just people that looked similar - I didn’t want the works they may have done to influence my work. Once I had begun my story, having all of my character sketches completed allowed me to write interactions that actually made sense. It also kept the characters from bleeding into one another because their templates dictated what their actions would be. Of course, these character sketches also altered the road that I wanted the story to go down. But in the end, it made the tale I was telling all the more believable.

What Happened to Your Story?
If you have written your sketches well and have given life to your characters, the story no longer belongs to you; this is not a bad thing. You are just the story teller! You are expressing what has happened in these people’s lives and if you don’t know enough about them, no one will believe you. On the other hand, if you know your characters well enough to both love and loathe them, readers will be eager to spend as much time as possible with the people that you have created.