To lighten & brighten the room ~

 

The couch area with two chairs definitely needs lighting up and the couch itself.  I would either recover the couch in a slightly lighter fabric or I would throw a few fun accessory cushions on the couch.  It is far more cost effective and less PT to change cushions if you eventually tire of the colour scheme.  Because violet dominates your current colour scheme, I would go for pastel yellow (complementary colour to violet on the colour wheel), duck egg blue, some splashes of white and a few patterned ones.  Perhaps even include some nature textile designs to ‘bring in’ some of the outdoors.  A vase either on your desk or one of the side tables bringing in some reflective glass, filled with white flowers of your choosing, would also lighten the mood.

 

Definitely bring in a large vintage mirror which will superbly reflect the outdoors.  Hang it either behind your chair or on the open space of wall to the left of your desk above the photo frames.  I would paint the ceiling a matt, off-white colour (not full white as this will be too stark against the dark wood).  This will reflect more light from your recessed ceiling lighting already installed, plus give the room the feeling of a much larger, brighter space.  It will make a big difference in the brightness.  The dark ceiling is heavy with the additional dark walls.  No window dressings are necessary.  I would avoid going for too bright colours as this will detract from that ranchy feel.  Stick with the neutrals of different shades with toned down colour that brings out the hues in your chairs.