One reason people have problems with collections is that they have been brainwashed by the contemporary cliche showing a single large painting on the one available wall of the room.
Most people just don't have the large work of art, primarily because they can't afford anything original in large scale. Of course, you can fake it: Framed printed cloth, a large rug or a textured weaving, even a photographic enlargement can be a relatively inexpensive substitute for fine art. For many people, however, clustering smaller works, would be preferable: small paintings, prints, photos or sculpture.
In a home I worked on, the young owners hoped eventually to acquire a fine collection of paintings. In the meantime, however, budgetary constraints made it impossible to try anything more expensive than small drawings or prints; their taste was good, but none of their acquisitions was large enough to dominate a wall.
To solve their need for an art wall, I designed a thick shelf of white plastic laminate, running from one end of the seating area to the other - a low, but strong horizontal line on the major wall of the room. For emphasis I arranged the furniture around it, making it the focal point.
The prints and drawings were hung above the shelf, or simply rested on it, an informal arrangement that instantly accommodates new acquisitions. The shelf is large enough to contain a sculpture, a plant or two or a decanter or coffee service when needed.
A word about construction. This shelf is thick for two reasons: The first, a narrow shelf would be out of scale with its importance as a focal point as well as with its length. The second is to allow for invisible support with L-shaped steel brackets painted to match the wall.
To highlight the prints, I painted the wall a rich brown, to match the carpeting, accenting the white background of the prints and the white shelf.
For more storage space, the same principle can be applied to a wall-hung, or floor-based storage cabinet. This can be modular, with a single counter to unite the several parts, or simply the individual tops, joining closely together, all the art on or above the cabinet top.
With track lighting, a simple system because it can be surface-mounted to your ceiling, or up-lights resting on the shelf and flooding the wall with light, your favorite things can easily become the focal point of any room.