See the (natural) light
You might underestimate how important natural light is for our wellbeing. It stimulates Serotonin which, in turn, lifts our mood and improves our productivity. Who wouldn’t want to feel happy and productive in an office?! Unfortunately, however, many offices do not have any access to natural light.
Sometimes, this might not be something that you can change without relocating or undergoing larger changes to your office space. LED lighting can be a good alternative if this is the case, as it is the closest alternative to natural light and has been proven to have the same positive impact on mood and productivity.
If you do, however, have access to natural light, maximise it as much as possible! You can do this by creating more of an open working space and not blocking out any sunlight with large or tall pieces of furniture, and putting large mirrors on the way to reflect natural light from the windows.