This is what've read:
Tone is the attitude of the author toward a subject. For example, the author can have a sympathetic tone.
Mood is how the work makes the reader feel. For example, a science might make the reader feel sad.
Writing style means the mechanical or technical aspects of writing and may be specific to the requirements of the subject or topic.
Voice means the unique worldview and word choices of the author. Basically, it's the author's unique "personality" in writing.
However, I'm still confused. How am I supposed to know the difference between what the tone (the author's attitude) and the character own attitude (narrative voice) is?
For example, I read this about the tone in Jane Eyre: "The tone of Jane Eyre is direct, perhaps even blunt. There is no prissy little-girl sensibility, but a startlingly independent, even skeptical perspective. At the age of 10, the orphan Jane already sees through the hypocrisy of her self-righteous Christian elders. She tells her bullying Aunt Reed, "People think you a good woman, but you are bad; hard-hearted. You are deceitful!" and "I am glad you are no relative of mine; I will never call you aunt again so long as I live. I will never come to see you when I am grown up; and if any one asks me how I liked you, and how you treated me, I will say that the very thought of you makes me sick."
Here, the writer of the piece says the tone (the author's attitude) is "direct, perhaps even blunt". But how am I supposed to know if this is the tone or if this is just Jane's narrative voice?
Furthermore, characters usually have some different views, values, opinions, attitudes from the author. How am I supposed to know the difference between the author's attitude and the character's attitude?
Here's an analysis of The Picture of Doran Gray to illustrate my point further: "The descriptions of Dorian's incredible physical beauty are also invested with the same kind of near-obsessive, swooning admiration:
Yes, he was certainly wonderfully handsome, with his finely curved scarlet lips, his frank blue eyes, his crisp gold hair. There was something in his face that made one trust him at once. All the candour of youth was there, as well as all youth's passionate purity. One felt that he had kept himself unspotted from the world. No wonder Basil Hallward worshipped him. (2.2)
However, because this was a book intended for publication and sale, the narrator has to come down pretty harshly on these immoral characters—the tone grows increasingly judgmental and critical towards the end of the novel. We start to see that Lord Henry is a truly warped and flawed being, and that Dorian himself grows less and less compelling as he gets more paranoid (after all, desperation is not sexy):
He was prisoned in thought. Memory, like a horrible malady, was eating his soul away. From time to time he seemed to see the eyes of Basil Hallward looking at him. Yet he felt he could not stay. The presence of Adrian Singleton troubled him. He wanted to be where no one would know who he was. He wanted to escape from himself. (16.16)
The tone of the narration is also extremely judgmental throughout with regards to characters who aren't worthy of praise—ones that are either too stupid or too uncultured to merit Wilde's interest, or are just women (for example, Mrs. Vane and Lord Henry's wife, Victoria)."
The analysis says that the tone becomes judgemental, but maybe it's just Doran himself who becomes judgmental. How would I know?