Got your hammer ready?
Put it down for now, as we have some work to do before we start banging all those nails in your pristine wall. (It's painful, but once you get the art up there, you'll be happy. I promise.)
Step One: Choose your wall
I always like to choose a wall that has some visibility, that is to say, not that "dead wall" around the corner in that room you never visit. It's nice when you walk into a room and there are some wonderful elements of interest that you or your guests can walk right up to and enjoy.
That's the other thing -- if you do have a wall that is unobstructed (where there is no furniture against it), such as in a dining room, or even a hallway or a stairwell, it will suits a grouping of smaller works the best.
Why? The artworks that are small and intimate can be seen at close proximity and enjoyed by everyone. Your guests won't be kneeling on your couch or leaning on your sideboard to get a glimpse of that one etching that caught their eye.
That all being said, the other side of the coin (or room!), is to use that piece of furniture against the wall (as mentioned, the couch or the sideboard) as an 'anchor' to the wall and the grouping. This is good when the wall is enormous and needs to be broken up visually to cut the expansive space down a bit. Hanging your grouping in that spot can help bring the viewer into the space and can make it feel more 'homey' like a good bookshelf can do.
Step Two: Gather ye artwork
Sizes should vary. The more variety of sizes, mediums, frame colours, the better! No, they shouldn't match. Choose black frames, gold ones and unframed works to add more elements of interest to the grouping. Throw in any artworks that have depth or texture -- oils, encaustics, 'objet' -- all will work well in your grouping.
Step Three: Lay Lady Lay (your composition)
Once all of your art is on the floor in front of you, in front of your wall of choice, you can see what you have to work with.
Find the piece that holds the most weight. It is probably the one that is the heaviest in terms of look, and maybe the largest in size. That one is your anchor piece and will be going in the middle, closest to the bottom of the grouping. Why? It creates an optical illusion when you hang the heaviest (again, visually) on the bottom, and allows the grouping to appear properly balanced. If it were hung high above some smaller lighter pieces, it would look top heavy.
Then begin placing your artworks on the floor in front of the wall, sprawling outward from the centre anchor piece. You may have to place them down, and move them around quite a bit before you get the hang of it and it starts to look right.
Composition can be a tricky business, but always keep in mind the weight issue. For instance, smaller works can together form the look of one. Two works stacked one on top of the other can balance one side of the anchor piece, while six smaller works on the other side, can have equal weight and look great randomly placed. A horizontally oriented piece (or panoramic) can balance well with two vertical artworks above or below it, visually forming a square. Play with balance that way and it can be easier to do.
The "outward sprawl" look and method allows you to add to the grouping over time. It looks eclectic and adds interest if you do it this way. Again, do not worry about matching or consistency as the more art you add the better it will look, but always keep in mind a balanced composition. Proper form will always win out.
Footnote: If you're still squeamish about getting to it, then you can always get some craft paper and start tracing and cutting out the shapes and sizes of the art you wish to hang. This way you can experiment directly on your wall (with some sticky tack on the paper), and see your grouping's composition before it's hung. I find standing over the actual artwork (maybe even with a step ladder) the best method, but the cut-out way works well too.
Step Four: Get Hanging -- Salon Style!
Bring out the hammer and start with the anchor piece. Hang on one side, then the other, then again and again, while keeping a sharp eye on balance. Do not worry about lining up the tops or bottoms of the art, as the more intentional randomness the better (and the easier it will be to add new art over time).
The Result: A wall that says "Personality lives here!"
The rewards are great and will give your home a fantastic, warm, eclectic look. Good luck!