Be bold with your wall pieces. Allow the size of framed art to "take up" the space it is occupying and be in the center point of that space. For example,if the wall space is wide, use a wide framed piece. Avoid using tiny framed pieces on a big wall.
Avoid hanging artwork too high. To keep an overall sense of balance and harmony in a space, start with the center of the piece at 5 feet up from the floor and then make any adjustments from that starting point. You may need to raise or lower the piece in relation to the other furnishings. Just be aware that eye level and a bit above is a comfortable point at which to view art.
Give artwork a little "breathing room" on all sides. Artwork hung above furniture should take up about 2/3 of the visual space. For framed art in a grouping, try not to have too much space between frames. This would normally be about 4 to 6 inches apart. You can use 2" for tighter groupings.