Good characterisation for me (when I'm reading) is a character doing things for reasons I understand and acting in ways consistent with who they are. When this doesn't happen I find the character less credible and also less likable. Characters are people I want to care about one way or another and I can't do that unless I understand on some level why they do what they do. Yes I'll even lump the villains into that catergory, especially the villains actually. I want to know the baddie the hero is up against is a complex and interesting person, capable of making smart decisions and outwitting the hero. If they weren't, then it would be no contest. A good example of poor characterisation was in a published novel I read recently. The author was clearly a great plot artist but didn't create multi-dimensional characters that I could believe in. One character a female, had been an abused child. So far so good. But the problems came in when this meek person suddenly morphed into a confident leader of people within the space of two paragraphs. There was no inner conflict, no self doubt, none of the emotions that plague people daily. Let alone to the magnitude you would expect in a child that had been abused and manipulated all her life. It just wasn't consistent or credible. Worse, she then went on to sleep with all the lead male characters for no real reason that I could tell. It bothered me so much that I didn't pick up the next book. Poorly written characters seem to mouthpiece the plot, they say things just because it needs saying rather than say what should be on their mind. A good test, is to have several characters in a conversation, and if you can't tell who is saying what, just from their speech (not the taglines at the end of it) then your characters don't stand out on their own and possibly aren't good characters.
