A good background can make or break an image.
If the background does not add to the image, you need to try to remove it or make it invisible. Either move your feet and change your angle to the subject or change your viewpoint to 'hide' the background.
The background can also be useful and should be included, using leading lines (tip #5) or colours to help emphasise the subject of your photograph.
Whatever you do be aware of your background to ensure you don't spoil your image.