Is painting the building outside of your budget? Plant some small shrubs along the wall (fence?).

Use color to differentiate the framing from the panels.

Painting the framing beams a contrasting, complimentary color would be a good start. What if you painted the apartment doors a color as well? Or...thinking a little differently... pick six colors that go together and do each one a "special" color. Might be fun for the residents. Since I don't see the street address anywhere, what about some large stylish street numbers on the panel piece above the carport in color? Shrubs along the fence line with variegated leaf color would liven it up.

I'd use a 3 color paint scheme. Paint the body 2 tones of the same color and put the darker color on the lower half of the building. Use a complimentary trim color that is lighter than the body. Paint the balconies and the roof eaves the trim color. As you eye follows these colors from ground toward the sky, the building will actually appear taller and make more sense visually than the mono-chrome scheme you currently have. It's going to be hard to do much with the upper story just above the carport unfortunately.

Mark out garden plots on the grassy area for residents to have their own garden, no matter how small. Turn over the soil and add a load of compost before adding edgings. Write apartment numbers on the edging of each one. Remember to "dial before you dig" to find utility lines that may be under the soil. Residents who are garden mad can help the ones who are unwilling/unable. Some residents will like to grow food.