First of all , day 10 of The Shred. I have hit level 3 and am able to wear a pair of pants that I could even get fastened a few months ago. The weight is holding steady but I assume muscle is heavier than fat. I know I am getting fitter but I still died when I did level 3. It will get there.
One of the interesting sections in Characters & Viewpoints is about how to handle backstory. Basically there are two ways -- the remembered past as a flashback, memory told, or quick reference. Which is mostly how authors handle backstory. Or the implied past -- expectation, habits and networks. An implied past can make the world seem like a much bigger place without even having to say what that past was. For example, Expectation: Jane threw herself on the ground and covered her head when she heard a car back fire, certain it was a gun shot.
Habit Every time Jane walked into a room, she instinctively checked for another exit, just in case she needed to get out quick.
Jane thought she wouldn't know anyone at the concert but in the course of five minutes she saw three people from work, two from her daughter's playgroup and five or six people whose faces she recognised but couldn't say from where. This was a very bad sign.
It is easier to believe in characters if you think they have past, complete with connections to other people. Anyway, I found it intriguing and useful to be reminded of the various tools in a writer's tool box.