Paint the walls, exchange the brown curtains for white ones

You could also pull your sofa into the room for a cozier feel.

Its a very nice room. But everything is medium brown. The easiest fix is to repaint to a much lighter beige for contrast and bring in a new rug with neutrals and subtle color. Better lighter window treatment would be next. Do you always keep the windows blacked out like the picture?

No they are only closed at night.

What's out there? If its green, it might be nice to add more green in your room.

I absolutely second a lighter wall color (beige with no yellow undertones- Barcelona beige) and pulling the sofa off the wall so it meets the rug(even if it means pulling the rug away from the tv a little bit). Also get long curtains that match new wall color. Also if it fits, put the side table w lamp on the other side of the couch- I think there’s still enough room to leave the tent there given this change? Maybe have tent opening face new walkway you’ve created behind sofa. Good luck!

or if you want a quick fix, get longer light cream curtains To match rug and see if it does the trick.

Blue tones?

Outside of the window is Woods. I can’t pull the sofa off of the wall because the sofa is a reclining sofa so I just wouldn’t look right.

Blue looks great with brown. It doesn't need to be bright blue. Start with a rug.

Add lighter color curtains as suggested. You need at least twice as many panels as you currently have. Change out the pictures over the sofa for a large piece of artwork that brings some color into the space. A rug like this still relates to your brown but brings in a bit more color that you can use as accents in pillows. https://www.rugsusa.com/rugsusa/rugs/kaleen-st-george/Chocolate/122656140-P.html

I added lighter curtains around the door and I don’t think it looks right.

Get a rug that's almost twice the size of the current one. Pull the chair next to the sofa. Get rid of the valances on the windows. Maybe replace all the blinds and curtains with woven wood shades.

Show us a picture of the lighter curtains around the door, please.

Ivory sheers & if keeping the bookcase paint between or paper between the shelves.

following

I am trying to add a photo of the curtains but it won’t post.

Be patient & wait for color to brighten & rotate b4 hitting the submit.

Please ignore the mess. I have not changed the balances yet, I just want to try a lighter color around the doors first.

What color is the walls?

Walls are medium to dark brown. The color is called caramelized onion. Groveraxle I love the rug and window coverings but not the chair there.

The woven is nice. Add green pillows for less browns. It will feel earthy & fresh. Then move chair to other side.

Have you considered just removing the window treatments altogether? It looks as if you don't need them for privacy, and your windows and doors are nice.

Near gate. :)

If not can we see room more?

Remove the valances over the windows and just keep the blinds there. The valances serve no purpose and add to the dark browns you are trying to avoid. Exchange the doorway drapes for white/cream drapes that match your moldings/blinds. Then paint your walls a much lighter color.

Nice room but more "usable" than cozy.

Drapes and valances would by my first change. White blinds without them would be more cheerful.

A lot of people don't like vertical blinds for patio doors but I do because it gives you more option for light/privacy control. You can get standard window blinds to match them -- whether you choose wood, faux wood or vinyl or even fabric..

Consider adding live potted plant(s) by the windows -- snake plants are low maintenance as are holiday cacti. Choosing the pots could give you an opportunity to experiment with adding color to the room without a drastic change or huge investment. Setting the pot on a rolling dolly would make a larger pot easier to move around for cleaning. Alternately, a plant stand/table or two could give you an opportunity to add more change to the room -- you could make a piece double as a plant stand and cat bed cabinet.

Peel and stick removable wallpaper could add some light / umph to the back wall of your shelving unit.

Instead of painting all the walls, you might consider painting the wall behind the tv wall as an accent wall -- or, if you're feeling bold, you could just paint the inside of the arch of the doorway(s) -- perhaps a deep wine burgundy red..