Like many people, I have dabbled in most of the practices of literary criticism; they all have value, though I have found several to speak to my interests and my personal canon more than others. I have enjoyed reading, occasionally used, and to different degrees internalised a few aspects of deconstructionist, structuralist, textualist, historical, biographical, and feminist modes of thinking about books. This kind of nomenclature is verbose, but useful here because it is easy to understand and historically not too inaccurate: modes of reading are universal but the recent history of criticism gives some of them names; it is more important for a reader's growth to have a finely developed mode of reading than a finely articulated one. In trying to convey correctly my sense of the possibilities of a developed literary ear I shall try to overarticulate as little as possible, and this discourse will be personal and irregular.
At present I am often mistaken for a strict textualist, though the fault is my own; I am certainly a textual primicist. Literature exists not in the text per se, I feel, but the friction of the act of creation against the primary conception, which is only reliably manifested in the text. For me the right experience of reading, perfectly realised, is sympathy with the author in specific moments of creation, seen through the filigree window of text on paper or on screen. Sometimes what imports in creation is unconscious, sometimes conscious; I am a far better reader of the conscious than the unconscious, and so, many kinds of symbolism I believe often elude me, and structuralism (which inherits from anthropology, and from Jung and Freud among others) is one of the things I have been least able to internalise. For me it is good lines, when I have sensitised myself to them, that most easily let me see into the author's mind. A good line is always a shared aesthetic experience between the reader and author, and is also contextually relevant and universal. To boot, often it is evident that the best lines were made up outside of the act of composition, perhaps originally in conversation or in contemplation unrelated to the book. Thus when I feel I can understand what would induce me to write the most striking expressions in a work, I feel I have gone as far as possible at the finest level of granularity to understanding the book; this understanding goes a long way to evaluating the larger scale importance of the `filler' in the book. (Of course filler is necessary to achieve a reasonable tone of voice, and every author, especially Shakespeare who wrote 100,000 lines, writes a lot of filler.) It is only through sympathy, which seems to happen at random, or rarely, but does happen if one looks for it, that one can see all the way through a text to its conception.
Here are a few examples: Yeats's poem, `The Fascination of What's Difficult' obviously began with the word `dolt,' clearly his feeling about some of his theatrical colleagues. The rhyme on `colt' created the Pegasus imagery (pegasus of course is a common correlative for poetic inspiration) and on `bolt' led to the image of the stable. The whole rest of the poem is simply built around this tension of hindered genius in the dynamic of these images. The rest is filler, and very skilfully rendered. In Prufrock, it is likely only two stanzas formed the original conception of the poem: the one containing `Do I dare disturb the universe?, etc,' which is a description of a specific feeling, and the one later containing, `the eyes the fix you in a formulated phrase, and when I am formulated, sprawling on a pin...' which is the much finer poetic realisation of a precise aporia that often happens in conversation. `The yellow fog' stanza was obviously interpolated from some other fragment of a poem. The rest-- the two stanzas on either side of the `sprawling on a pin,' of approximately the same shape, lack the immediacy of the middle one and are simply very good filler. Likewise, all the stanzas up to `Do I dare...,' again with a similar stanza shape, are simply atmospherics that were designed around the feeling of `do I dare.' The genius of the poem is in fact that Eliot's filler is of a far higher poetic order than in the Yeats poem, and second, that while the poem ought to have ended at the line, `of lonely men in shirtsleeves, leaning out of windows,' Eliot effectively starts to write a second poem-- all filler-- designed to give the first half greater musical and psychological resonance. A third example is that the first quatrain of Keats's lovely sonnet, `Bright star, would I were stedfast as thou art,' is more awkward than it needed to be. One should ask, why does the poet write these awkward lines-- what would induce me to do it? A little bit of thought reveals that Keats probably switched lines three and four without rewriting substantially-- he was probably originally writing a Petrarchan sonnet with an abba rhyme scheme rather than abab, but later for some reason switched to the Shakespearean form. It is for this reason that first lines of books are always so interesting-- by the time the author as finished writing the book, she probably has 5,000 sentences, and any one of them could be retooled for the first line if it is relevant. Also the process of writing produces all kinds of sawdust, some of which may have been perfect somewhere, but not anywhere in the book. Likewise, the first line is very likely culled from somewhere else in the writer's life-- examples which come to mind are the first line of Pride and Prejudice, or the first line of A Tale of Two Cities.
I know I have taken up a lot of your time with this response, and I thank you for reading. Obviously a whole book or a whole poem is more than a series of lines which may be great or filler. In thinking about a larger work I also try to achieve sympathy with the author by understanding its structural principles. Some novels or poems were written from beginning to end (such as either Byron's Don Juan or mostly Wordsworth's Prelude; but the organising principle of the Prelude is preexisting while Don Juan was composed largely impromptu); some were outlined and some authors disdain that procrustean bed. Some writers write with a calendar, and some do not. Everyone inserts fragments of his or her friends and fragments of themselves, for this is all one has to go by; but for some authors the fragments are bigger than others. In Huxley the fragments are bigger than in Joyce, and they are bigger in Joyce than in Austen, and in my strongly held opinion for which I have no direct evidence whatsoever, bigger in Austen than in Shakespeare or in Homer, and perhaps often bigger in Shakespeare or Homer than in Blake. This is by no means a measure of literary quality-- Joyce is every bit as good a writer as Austen, and Point Counter Point is one of my favourite novels, even though D.H. Lawrence is more alive in that book than in his own works. I never let biographical criticism inform my reading of a work initially; but I must read literature by the light of authorial bias or experience when the work colours the light in turn because observed two-way communication is evidence of communication. Therefore too, any work for which biographical evidence is missing, such as Shakespeare's Sonnets, is more enigmatic than if that detail were available. In these cases, one must be wary of drawing conclusions simply because nobody is likely to be able to controvert them. Finally, by remembering the large scale progression of a work, whether of chapters in a book or stanzas in a poem, or cantos in a long poem, one can work back to a weaker kind of sympathy with the author over the months or years of composition (or days, in the case of Samuel Johnson's delightful novel Rasselas). This is for me where primarily textual criticism meets the biographical point of view and very tenuously shakes its hand.
I would finally add that feeling for a book's time period (as Michelle says, both of composition and setting), and for the author's place in it, is ineluctably the largest part of appreciation of a book. Moreover, it cannot be put on like a jacket in any way, except the most gradual. I have not found comments from others to help me much in gaining sympathy for an era, though reading their books helps a little. What helps the most is simply reading a large number of books contemporary with each other, and the requisite history and criticism as well, but only where necessary and not in excess. For me, I know a few times and places well-- not perhaps so well as the present, because my impressions of the past are more stylised and certain, probably wrong and certainly less fluid than for the present; but my appreciation of books from these milieux is incomparably greater than books I pick up at random. The brighter spotlights in time for me involve fourth century BC Athens, Rome from 50 BC to 50 AD, London from 1550 to 1643, and London from about 1770 to about 1815, and perhaps London in the Edwardian and early Georgian eras, though the centrality of London here is less important. For the eras sandwiched among these, I feel quite out of place in the Victorian era compared either to the Edwardian or the Regency, and while my troubles are not so great, Cromwell's or Early Georgian England are very much more foreign to me than Elizabethan/Jacobean or late Georgian England. What I would suggest you do, if you want to, is find a period that you love and read a few dozen books from the era-- literature, whether novels, drama, poetry or whatever is relevant, as well as nonfiction, even that era's history books or their literary criticism or the letters of your favourite authors....