For colored walls, try to match colors within the painting or mat to give a coordinated look. Groupings of large paintings will overwhelm a small room. A selection of small works, grouped tightly together, turn awkward nooks and alcoves into inviting niches. Symmetrical displays of an even number of pieces which are evenly spaced are the easiest to create. Asymmetrical displays work best if the pieces of art being hung are of different sizes, shapes and colors.
Planning prevents wall damage.
Use graph paper to sketch the available wall space to get an idea whether the size and scale of the pieces will work well together. Alternatively, cut pieces of scrap paper to the approximate proportions of the work to be hung and rearrange until you have your small grouping conceptualized. Steal a tip that gallery staff use when hanging exhibitions. Lay the work on the floor or against the wall to get a feel for its placement. This will also let you see how the light will reflect on the work.