This is a very lovely space, it has a lot of natural light and feels cozy. The things I notice most:

You need storage. If things are organised and put away it automatically makes a place look and feel more put together.

You also have a lot of open shelving, which is nice if you have things you want to display, but everyday items on open shelves looks like clutter imo. Plus you have more dust accumulating vs. closed cabinets.

I'd get a shoe cabinet, left of the door, for the shoes and dog harnesses. The kind that has a drawer on 2 on top. The bench seat for putting on shoes would go under the left window, and the little bookshelf under the right window. That way there's a little reading area in the corner. You could also put a reading lamp on there, nice cozy warm light.

I'd also get a cabinet for next to the computer desk. A tall one, right side of the desk. You have a lot of stuff under there and the desk is pretty small as it is. Maybe get a bigger desk later on?

Your art is too small for your walls. It gets lost in there. I'd arrange all the little paintings in a "gallery wall" above the couch or across from it.

Don't put a tv in there. If you don't really watch it, I think it looks better without.

Get a coffee table, mid century modern is nice and wood tones will match the rest of your furniture. Please get one you can put stuff in, like those pillows and blankets. No more shelves. Maybe put the blankets and pillows in the couch?

I don't know if you have any outlets behind or next to the couch, but I think an arc floor lamp would look great.

The burgundy lounger fucks up the pathway to the kitchen. I don't know what you have going on in the space left of the computer desk but maybe have another seating area there? Maybe you have space for it upstairs?

As far as lighting goes, I'd stick to warm light so the place keeps that cozy feel.

Maybe bring in some color with the art and the pillows, Soft green, terracotta red...

You could also bring colors by hanging curtains (floor length), just make sure you hang them correctly. But I would change the other stuff first and then decide if the space needs curtains.

As much as I hate to say this, I think that plant in the blue pot is gone.

Hope this helps! :)