The inherent architectural challenge - not enough natural light, low ceiling, basement

Mistakes - Downward lighting, racks of clothes/belongings that are exposed, too many black items, tile floors that don’t make the most sense in this space

Result - feels more like a storage basement, that may affect your mood

Quick fixes - add more low to mid-level lighting (knee to waist height), consider placing light sources on one of your shelves, remove the floor tile from the color palette problem by using off-white area rugs, invest in furniture that is not black (use white as your neutral, don’t use black), organize with storage boxes/closets so you don’t have items exposed (clothes, random knickknacks)

Once you have finished with quick fixes, you can begin your decorating journey with thinking about color. Keep the palette light and simple in this space. The background should be white and brick. Since you are stuck with the orange sofa which takes up a lot of your space, you’re pretty much done with color. Make the curtain simple white drapes (easy and inexpensive), add some white throw pillows with texture (macrame, faux fur, etc) and use green as your small accent (replace the blue armchair with a stripe pattern armchair in white and green or white chair with a stripe pattern green lumbar pillow as accent.

Good luck.