My living room needs warmth

You can paint a accent wall. (one wall a color that you like) then maybe get some wood trim (molding) with a design on it to put up around the roo. Good luck. I am sure you'll do great!:-)

Add bright colors to make it "pop". Your color scheme so far seems to be all in the brown and tan families. Try your favorite "funky" color for throw pillows etc. By "funky" colors, I mean a color that you wouldn't want an entire wall to be painted, but want to add the appeal of a "popping color".

I use turquoise and aqua's with a minor splash of orange (my favorite color), against taupe walls and a brown wood exposed ceiling with beams.

Just by adding small "pops" of color will get you started.

Have fun with it!

That shelf can be your salvation. You can put items up there that are favorite finds but may not have practical use. Think of really old books or antique toys. Conversations type pieces. Use only a few and vary the height and texture of items. This will bring "you" into the room.

You could also add some wallpaper and bright pictures.

Plants help every room! Especially in decorative pots.

I know this sounds harsh, but your room lacks 4 things: (1) color, (2) pattern, (3) personality, and (4) life. BUT, I am not being mean, I am a retired interior decorator, so please let me explain!

(1) Color: The color scheme of a room starts with one piece of pattern, so here I'd take it from the rug. Looks like it contains aqua, brown, light green, rust or rose, and cream. I would paint the entire room a light aqua-y green (like the large dot in your chair pillow, if I'm seeing that right).

If the color in the rug is rust (or is it rose?), whichever, find an 18" toss pillow in that for the sofa. (2) Pattern: Now find drapes in a fairly large pattern involving most of the colors of the rug. [NOTE: hang the panels over the wall just to the edge of the window frame. They should never cover the glass. Makes the windows look bigger and lets in more light!] Get either another panel to make two toss pillows for the sofa from, or get extra fabric if you have the panels made. You want to pull this "largest dose of pattern" in the room across the room in at least three places: the window, the sofa, and into the dining area. So with the extra fabric, use it on your dining room table as a runner or on your chairs somehow. (I assume since you said you rent, that you can see the dining room from the living room.)

Now with color on your walls and pattern around the room, the next thing you need to tackle is (3) Personality: I see a few accessories on the mantel, but not a lot of things that tell me much about you. A home is a reflection of the people who live there; it should tell your story. Move the mirror over the fireplace to another place -- the foyer area perhaps. Choose a large piece of art that you love. If your budget is tight, go to yard sales and thrift stores. Who cares where you got it if you love it?! My house if full of "thrifty buys"! Now gather some books you've read -- libraries have sales, and thrift stores are another great source. And buy things you would read :-) Stack 3 of them and place that vase atop the stack. Lean two others against the vase. Now the grouping looks far more interesting than just the plain vase. On the other end of the mantel, stand the tall figure with perhaps a candle about 1/3 her height and, again, a few books. In the center, the clock. On the hearth, fill the blue and white planter with -- you guessed it! -- a plant that's nice and full and has two colors to it, such as Chinese evergreen.

Lastly, (4) Life. This is where plants come in. I don't care if they are silk or real. If you have pets, some plants are poisonous, so be careful. If you use silk, keep them dust-free (blow-dry them!). But two green plants or one green and some fresh flowers (on that coffee table with some books!) make a room come to life.

Whew! Enjoy.

Artwork with color in it. Hang a tapestry. Make a shadow box.

We really need more pictures in order to give good advice. We should see all of all four walls. The pic with the rug and curtains is just too plain dark. Is there a reason the chair's back is to the fireplace? Also the skinny shelf seems out of place with nothing on the walls beneath it. More pictures please.

Throws, plants, baskets, pictures, mirrors, spotlights and string lights will add warmth to every room. Also vary the texture of your decorative items; shiny, smooth ruffled, curved, rough, woven, and so forth. ☺️

I would use some lighter color drapes, and throw rugs and pillows with some color.Greenery real or fake always warms up a place

The shelf at the top is definitely a challenge! Add some "spiller" plants on the shelf such as an ivy. Textured pillows and throws could also add a little warmth to the room. Lighting also makes a difference! I have a small lamp that I have on an end table that gives off a soft light in the room in the evenings when it's time to tone things down a bit. You might also have some of your favorite pictures of friends/family put on canvas and add to an end table or shelf.

I agree with all the suggestions about plants and personalizing the space. That high shelf looks like it would be super easy to take down. I'd cut it into multiple smaller sheles and paint them an accent color. Re-hang them in waterever configuration is appealing to you so their more at eye level,use up more of the wall evenly. Looks like a cute space that just needs your personal stamp to finish it off.