Your choice of colour will heighten or calm your mood and alter not only your visual perception but also your perception of temperature. A pale blue window blind in a sunny room will give a much fresher feel to the room than a warm coloured terracotta or pink blind.
Try to choose a colour that you really like and if you are not sure what that colour is then take a look inside your wardrobe, it will give you a clue to your subconscious favourites. Go with a colour that you know you like rather than one that is currently in fashion as you may well tire of it more quickly. If you are still unsure, then play safe with white as it always looks fresh and smart especially with a bold colour as the contrast. Whereas for a more subtle look go for creams and taupes.