How to redecorate my room?

First off lets just say to give redecorating advice over the internet without seeing anything is hard to do but anyways. From what you said above I would do a tan with a dark brown accent wall then alternate opposite colors with the trim/base/crown moldings and doors. This way you are staying neutral and then you can use your green and yellow as accent colors, or whatever you decide on. This way you have great design with colors and yet flexible with the things you put in it.Hope this helps.