Here you have your great story idea. You have it in your head how it is supposed to go and where its happening. You are set for that million-seller, award winning novel. Now you just have to get it down on paper, or word processor. Boom! You get to writing and the first character comes up. Your face gets that blank look to it and your enthusiasm fades. Who is this person? Where is he from? Do you have any background on him? How did he get to here? EEEEEEK! I will tell you this, sometimes, most of the time, you are not writing about a story. You are writing about a character, or several. Sometimes the character is so obvious that creation is easy. Joe Shmo is a mechanic who wins the lottery, or Jane Whatsherface moves to the beach into an old lighthouse. But is it this easy every time? Not on your life!
If you go into your story without some sort of idea about your characters, it is like going cross-country driving without ever opening a map. The journey is slow and arduous. There will be times where you forget that you had said he had blue eyes and in later chapters say they are green. A good plan of the characters themselves is always a good idea. You have the perfect story, but the story is just the skeleton, the bones. Now to put flesh on them bones, you need characters worthy to be put into your story (award winning, remember?).
Names fail to come to me when I don't think of the characters as people. Yes, I know they are make believe, but when you write about them, they come to life, don't they? Have you ever read a book where the characters seemed as flat as the pages they were written on?
YOU HAVE THE POWER!
You made this world. Give the characters life. Think of them as living, breathing beings that will jump off the pages at any time. You have the power to do this. If you aren't interested in these characters, what makes you think that readers will? Its in your hands. Make notes, describe to yourself each and every character. Then write. Some characters will just pop out out of the blue and thats OK. Your in your flow by then. Create at will and enjoy your little creations. Allow yourself to get mad at them, cry with them and even get scared for them. You now have flesh on bone that you have brought to life on your own, and that makes you a writer...or a mad scientist...I am still thinking on that one.