What can you do about it?
Adding trees, awnings, lattices, or vines to shade exposed areas of your home's exterior will help reduce your cooling load (the energy required to keep your home cool).
Use several strategies (like curtains, window film, or landscaping) to shade windows during the summer.
Focus on shading east, west, and south facing walls.
Install window screens.
Coupled with shade from landscaping, window screens can maximize shade potential for your home. Use screens with a shading coefficient of 0.76 or lower to reduce heat radiation.
Add awnings and overhangs to windows.
Awnings and overhangs need to be close to the top of windows to effectively shade the glass. A good rule of thumb is to cover half the surface of glass at the summer solstice (e.g. A 30" overhang at the header will cover the top half of a 4' tall window).
Place trees appropriately to optimize solar gain.
Plant evergreen trees on the west and east sides of the house to keep out heat all year long. Use deciduous trees on the south because during the winter, after dropping their leaves, the branches will filter the sun and provide desirable partial passive heating.
When building a new home or adding an addtional, consider passive design features.
Incorporating passive design features in to new construction costs little to nothing. The benefits are greatest when the entire design can be taken into consideration. The most important things to consider are site orientation and layout.