The bedroom is the part of the house where we spend most of the time -specially teenagers– so it must fulfill the needs of those who occupy it. A juvenile room should combine a zone for rest and other for studying and using the computer, both as separated from each other as possible. The choice of the bed must be done with a practical sense, the ideal size being 90cm, stuck to the wall so it can be used also as a sofa; the nest beds or berths that shelter below a study zone will help to take advantage of space.
A study table with space for the computer, printer, etc., accompanied by an ergonomic chair will be of great usefulness to motivate long hours of study (or endless hours of computer chat, we must admit). In the wall near to the table or in the top of it you can place shelves for books and decorative complements (photo holders, souvenirs, trophies, etc), to make it look more cozy.
As for the colours you may try soft tones that invite to relaxation: sky blue, pink, mauve clear, beige, green water, etc. However, it all depends on the character and gender of your teenage child (a boy probably will not tolerate his bedroom to be painted in pink, we assume). Remember that a juvenile rooms must have the personal touch of the teenager who occupies it so the accessories should be those which speak about his or her taste and interests, always keeping some order and harmony.