I have a small balcony, how can I add the most color?

I found 2 1/2' planters that attach to the rail. Multicolor wave petunias in sunny areas or impatiens in shade.

plants in painted pots

You can hang a variety of flowers. Different colored furniture works too- mismatched chairs are very "in" right now.

There are some good ideas already given! One of the things I'm going to do this summer is paint a carpet runner with various colors to brighten up my front porch. You can buy plain colored carpet runners by the foot at hardware stores. I happen to have grey (which I didn't buy and don't like) but to turn lemons into a lemonade stand ;) I'm going to tape off a design with tape by just crossing the tape haphazardly leaving behind grey various size triangles and other shapes. Then I'm going to paint them in multiple bright colors. You could do something like that or if you can draw/paint do your own artistic rug for the floor. It will be fun! HTH

Thank you all very much, you gave me some wonderful ideas!

I found a very small chair with the seat already missing. It's about 12 inches wide and about 3 feet high, already painted shabby. My husband built a wire cage holder in the center. I planted Dracaena in the center, verbena, and geranium in the front, with trailing vine off to the side. Would fit perfectly on a small porch, condo balcony and displays lots of color. You can get a cheap plastic oil pan to put underneath if you want to catch the overflow of water.