Modern bridges come in all sorts of designs and sizes and tend to feature clean, elegant lines and repeating structural patterns, but when viewed close up may be less photogenic than traditional structures because they are built using materials such as reinforced concrete.
Walk along the banks at either end of the bridge and observe how the view changes before selecting a photographic viewpoint. Look for foliage, archways or other structures that might be used to frame the composition and hence add depth and context. All sorts of angles and approaches are possible, but it is often the case that the strongest feature of a modern bridge is its apparent structural simplicity.
The image above was taken from the deck of a ship passing through the Suez Canal and shows the modern bridge linking the Sanai Peninsula with the continent of Africa. Its cable-stayed central span has characteristic elegant lines and its length makes it appear quite delicate. The wake of the ship and the converging sides of the canal lead the eye in to the image, and the featureless desert and clear sky tend to emphasize the clean lines of the structure.