Great control and great discipline are necessary when you reach your own editing stage of the book, but in the early stages you have to be prepared to let anything happen and to get it wrong or go off track. The development of a character is not smooth or simple - it is as tricky as meeting someone new whom you would like to know better.
I wanted to invent myself as a fictional character. And I did, and it has caused a great deal of confusion.
My characters are always on the outside; the spotlight's not on them. But they do get somewhere.
A character has a distinctive voice - you should be able to hear them in your head and conduct a conversation with them while you're out walking. If the answers surprise you, you know it's the character speaking and not you.
It is important not to force a character into something. Fiction writers can be too controlling - usually that's a terror of our own unconscious processes.
