During the 1970s it became quite common to have one wall in a room as a feature wall. The feature wall would either be covered in striking wallpaper, while the other three walls were painted a complimentary colour or covered in a constrasting wallpaper. This can still look quite good in the right style and size of room but there are also plenty of other ways of making a feature wall in a room.
You could try making a display of photo frames on your feature wall. Either have a mix of frames of different styles and sizes or make a geometric display with frames which are exactly the same.
Instead of covering the whole wall with wallpaper, you could have a feature panel of wallpaper. Make sure you choose a print which is very striking or unusual for maximum effect.
Construct a series of small shelves or ledges on your feature wall. They can either be painted in the same colour as your wall or in a contrasting colour. Display mementoes and artefacts from your travels or attractive glassware that you don’t want hidden away.
Cover your feature wall with a large wall hanging, tapestry or rug. Have a wall of mirrors and don’t be frightened to mix up styles and colours. Or you could be really bold and install a custom made radiator on your feature wall. This might be especially suitable for a kitchen. There are companies which make radiators which are more of a work of art than just a plain, functioning part of a central heating system.