I love that color, so cozy and organic. :) Your furniture is light, which helps the brightness factor ... I’d just look for art you like and use that. Maybe canvas prints, or art with light backgrounds. Green, to me, is very neutral — you could add light blue, white, cream, lighter greens, etc. I don’t like to suggest specific art because it’s a very individual thing, but ... A map of the area, like this, would be fun — A decorative mirror might be nice, too, to reflect light and color. Definitely do a search for things like ‘art for dark green walls’ ... ‘lake art’ ... etc ... lots of inspiration comes up.

I agree with adding curtains and pictures on the walls. Paint is one of the most inexpensive items in decor. Gray is a cool color and beige is a warm color. That's probably why your room doesn't look right. Changing the walls to a warm color may work well. Cool colors: bright white, ice cool pastels, black, gray, royal blue, purple, bright yellow, pine green, Kelly green, forest green. Warm colors: off-white, sand, beige, tan, brown, olive green, peach, orange, golden yellow. Painting your walls a warm light olive green may work well. https://www.sherwin-williams.com/homeowners/color/find-and-explore-colors/paint-colors-by-family/SW9037-baby-bok-choy In my opinion, buying upholstered furniture at a second hand shop may not be the best idea - they may have bugs in them. Wood furniture is ok to buy there, because it can be cleaned. If there are bugs in upholstered furniture, you may not be able to see it and it may be impossible to get cleaned.

It doesn't need much. Hang fabric in the closet door. The furniture arrangement is nice. Hang a nice canvas over a narrower, taller dresser. Change the window shades to something not so dark. Paint the accent wall like the rest of the room like you mentioned. Definitely get rid of the tall dead looking dry arrangement next to the bed. Remove all the small pieces of decor, it's too cluttered. Just your one glass urn on the heater. Put a nice chair by the left window-a coaster on the heater, under the right window place some plants on top of an open shelfing unit that fits under the window to use to hold the router and coffee table books. I think the palm fan can go over the bed above the panels, maybe with your basket wall. Get matching night stands/lamps. Hang three matching framed prints in a row on the wall opposite the window. Their glass will reflect the light.

I’m a bit challenged trying to visualize this room as a whole. I think that how much use for going in/out the sliders needs to be factored in. The front slider next to the window is the most challenging IMO since there’s no room for any window covering to stack completely off the glass on the fixed panel side of slider. I agree the same fabric & treatment should be used for all windows. I think I would hang separate drapery panels over each window. For the front slider & window I’d use the same length panels for both slider & window for a better look when closed. That slider - I’d have drapes that open in middle & pull to each side. The corner fixed panel will always be partially covered with the open panel on left. The drape for panel that slides should stack completely off the glass so that door handle can be easily accessed. The window would be traditional drape open in middle & stack completely back off glass on both sides. Two rods for each window - sheers on inside rod & drapes on outside so the 2 coverings can be open closed separately. When closed, this wall would appear as a complete wall of drapes. As for color - don’t know if you’re wanting dark blue or thinking that’s room darkening. Room darkening drapes are available in many colors. Slider in dressing area should have same treatment but sounds like with 16” space on each side the drapes can stack completely off the slider on each side. Whether that slider has sheers or not depends on the privacy issue. Maybe only drapes on that one - no sheers.