Many years ago when my daughters were teenagers I installed a double curtain/drapes rail - the back one was a cross over one with a drawer string to the one side and the front was a straight one with no cord but. I made a valance in the same way as the drapes, with a drop of about 40cm and hung this across the front track. I used wide curtain tape at the top that had about three rows of attachment options for the individual hooks that were used tohang both sets of drapes (the front ones as well as the ones on the track at the back. I had floor length drapes for the ones at the back and it looked really good with tie-backs I also made and attacjed with brass style cup hooks especially purchased from drape shop. I will see if I can find a photo and post it for you to see. Surprisingly it was in the same colours of pink, turquoise and white that you have chosen. The valance made in this way is really easy and can be removed for cleaning from time to time. Both my drapes as well as my valance was lined with normal polycotton fabric.

This is one of the more difficult design dilemmas I've seen on here! I certainly feel for you and wish there were some easy solutions. I think there's way too much stuff on display and wonder if you could remove some of the shelves and any equipment that's not going to be used. There's an area in the second picture where it appears there are beige walls with some repairs on them (?) so I'd suggest painting them. If you can repaint the room, I'd suggest a light golden yellow to give a feeling of natural daylight in this window-less space. If you used Sherwin Williams SW 7685 WHITE RAISIN you'd be picking up the colour of the wood furniture and making the furniture blend into the whole room colour scheme (less colour contrast means more cohesion and it will be more restful for the eyes). If you can do anything about the lighting, I would recommend changing it. You may have a local program that would cover some of the expense of upgrading the lighting with new more energy efficient fixtures that would give you a better quality of light and lower operating costs. I can practically hear these lights humming when I look at the pictures! So my best advice is to pare down the visual clutter. If you can clear out a significant amount of it, you can add back some things like posters for inspiration and amusement, showing a bit of your own personality.

This is old school since I am 51, but I remember when I was in 5th grade, my teacher was also an artist on the side. Needless to say, I still remember her bulletin boards. One of the "prizes" for doing the best academically, was to be able to stay after school and "help" her with the bulletin boards. Although things have changed, she always said "less is more" and she would changer her 2 large boards monthly, but she would not go outside the bulletin boards like the other teachers. Her one exemption, is that she would post academic work outside the classroom in the hallway. Somehow, I still remember the times tables, the writing rules, and science articles. I now teach adults, but I try to remember her rules. I try not to overload my classroom with charts, maps, or photos.

I like the suggestions of painting a beige on walls and lighter natural fabric drapes. Another focal pop would be to wallpaper one wall or do reclaimed wood on one wall or do a wash or glaze on one wall - get that accent wall then you might be able to keep the dark walls everywhere else is you paint the trim a darker shade of cream. The art is too small. Possibly do a gallery wall or a large mirror with a rustic frame and 2 sconces on both sides of the mirror.