Here’s a writing trick that’s so simple and so effective that I’m surprised I haven’t read it elsewhere. (And if it has been discussed elsewhere, someone post the link so I can give proper credit. I’m too lazy to Google for it.)
The trick is: cast all of the characters in your story with recognizable Hollywood actors as you write.
Why? The reason is very simple. It’s the easiest way to keep track of the details about your characters from eye and hair color to voice inflection and mannerism. After you’ve spent a month or two following an alternate plotline, by the time you return to the main story you may not remember what color the main character’s hair is, or whether the viscount’s sister’s brother-in-law was supposed to be skinny or fat.
But chances are you do remember what Sean Connery looks like with your eyes closed. You could describe Kevin Bacon circa Footloose or James Doohan circa The Wrath of Khan without any mental strain whatsoever. You know exactly how sassy Mary Elizabeth Mastrantonio was in The Abyss, and how her voice sounded, and you probably have a good idea of how she’d react when confronted with a robot rebellion on the fourth moon of Xigg. (Mary Elizabeth, incidentally, was the model I used for a character in Infoquake. If you’ve read the book, you’ll know who.)
My first reaction when I thought up this technique was that it would inhibit the writer’s creativity. On the contrary, it sets you free to focus that creative brain of yours on more important matters. It’s just a mnemonic device to help you remember details. And with the wide range of recognizable Hollywood actors out there, you’re certain to find someone that you can cast for every character in your book.
Is this going to spoil your readers’ imaginations? Not at all. Obviously you’re not going to tell them who you’ve cast. And I defy you to write a description of any Hollywood actor that your readers will be able to recognize, without being given the name. (Okay, I’m sure there are a few. Danny DeVito. Gilbert Gottfried. John Candy.)
So go write a casting sheet for every character in your novel or short story. Yes, every single damn one, major or minor. And don’t worry, through the magic of the imagination, you won’t even have to pay any royalties.