When I start to write, I like to keep everything neat and organized. In fact, I’ll keep a nice folder with my characters taped into it along with any notes or print outs I’ve had. Even changes to the outline are kept in my folder. At the end of writing, I’ll usually put the publication date on the folder and file it away.
Developing characters when I’m writing utilizes a system that I learned when reading a book a long time ago. It was to create a note card with the information for each of your characters. This is something that you can refer back to multiple times as you are writing.
A huge issue is when there is a discrepancy between what happens at the beginning to what happens later. Eye colors change. Hair colors change. Name and name spelling changes. Yes. I’ve seen all of these in books that I have read recently. The way to solve this is to have it clarified at the beginning. As soon as you are creating these characters.
Create a template that you can use that keeps track of all of the pertinent information. Then use it.