Well, this is IMHO so as long as you guys respectfully disagree, it’s cool 
Seriously tho I lived for many years with a bookshelf in the living room until my mom covered it up with a nice cloth (granted, not a bedsheet) on a tension rod and it looked fabulous. Brought the whole room together. In my eyes, it gets rid of a whole bunch of clutter.
But that’s just me. I’m totally not a book fiend but some people are, so that’s cool.
Well, I’m sure it did look nice when she did it, but the mental picture I got from your description was horrifying. 
Arranging the books more or less by size and lining the spines up, as** Harriet **suggests, does make them look nicer.
Your answers are really helping clarify things for me. I realized the most significant thing in the room is a red couch. If I only paint one wall it will be the one behind it. I realized it doesn’t make sense to move pictures around till I paint the wall.
Once I paint the wall I can do the stitch witchery thing for the valances on the window on that wall (only window).
Whoever said organize then organize some more, I will take that to heart. Whoever said cover up the books, not gonna happen. 
so I have a starting point! Pick paint color for wall behind couch. Yay!
if you want to be foo-foo with the books, taking off the dust covers makes shelves look less jumbled and the books have that “ageless” look.
ace hardware store has these really nifty paint brochures that are labeled “playful”, “peaceful”, “traditional” etc. inside they have a page that has colour choices in 4’s . a big square and 3 smaller chips. the big square would be the wall colour, and the smaller chips would be trim, furniture, accent things. it is really helpfull.
I am, but my particular book collection isn’t very pretty. I used to keep it in the living room, but I’ll admit things look a lot nicer now that I’ve moved the bookshelves into a closet.
A red couch you say?! Cool, is it leather? You could jump start your whole scheme with that couch. For the wall color behind the couch, I’m seeing muted earth tones, something that will make that red pop. Also peel and stick wall decals ala whatisblik can spruce up a room.
Mirrors are useful for decorating, put one over a narrow hall table, or cabinet. Small table lamps can softly light up a dark corner, and throw rugs can help define or separate living areas.
I have an apartment where one tenant painted one short wall crayon yellow and one wall across the room crayon green. Catches you off guard at first, but every new prospective tenant who’s viewed it said they would keep the accent walls even though I assured them they would be painted to suit.
And that was all it took to make her room decorated.
I agree with chela about mirrors. One of the few things I have managed to put on my walls since I moved in (4 years ago) is a nicely framed, somewhat large mirror in my entryway/living room. It does make a big difference!