Screenwriting : Character development by Deryc Miller

Look at movies/TV you admire and break down those characters, using the breakdown as a model for yourself.

Give them flaws.

Since no matter what I do, everything goes through the filter of me, so I start out mining my personal emotions and fears for keys to characters. Every one of them is part me. I look at it as cheap therapy. So I have to start by admitting what my failings and fears and flaws are, and then work through them in the skin of the character. And what Jim said: story and character are connected. Here's a Script Tip I expanded into a chapter in one of my danged books (I think the Protagonist one): http://www.scriptsecrets.net/tips/tip166.htm

I start writing (sometimes stuff that isn't going to be in the story) and I learn my characters. I am willing to rewrite a lot. I sometimes get into a scene and think "what the hell are they going to do?" I write a few versions and figure out what works. This results in me having to go back and rewrite previous scenes so my characters are true to themselves. It is a great way discovering people and giving your thinking the freedom to evolve.

Ask them what their deal breakers are and what secret they are keeping. And, depending on the genre, try to diagnose your characters. what's their pathology. knowing this may give them greater depth and give you more fodder to work with in their actions, reactions & arc.

Base the characters on people you know, or have had experience of. This can be school-teachers, friends, relations, colleagues. Some of the most memorable characters, particularly from comedy, have been based on someone the writer/performer knew. Although it's slightly different for books, I've based several characters in my novels on my friends. It works well I find. Good luck.

Good answers above.. one more - sometimes you can draw character out of a prop. Does your character have something on his/her nightstand that they look at every night? A business card from an old fling? A piece of jewelry? I personally feel like good story will trump good character... but as a fellow amateur writer, you have to have both. And if you don't have good character, EVERY single review will call that out. Look at Two Guns - pretty damn good story, characters are kind of meh except for one guy is 'the womanizer.' But you get Mark Wahlberg, Denzel and Paula Patton and I don't think anyone will be complaining about lack of character any more.

yes, Joe, but that movie got put together because of a packaging agent and big money paydays for its stars. It had nothing to do with character.