How should i decorate my half of the room without changing the wallpaper or carpet?

I don't know how big your room is for space but maybe put up a bigish fancy mirror, if your wall still has a lot of space some canvas pictures (i don't know the colour of the wall either so pick a matchin picture, my wall is a shiny silver wallpaper and i have a black + white picture of new york up!) or put some shelves and cover with accessories. Add a nice rug and a beenbag or whatever you have room for with lots of cushions?