Check and clean the vents in your attic and make sure they are open and functioning properly. Homes built before the 1950s often do not have soffit inlet vents. In this case, see if there are exhaust fans or windows that can be opened.
Examine any outlet vents in your roof, gables or ridgeline. Excessive heat rises and will look for an outlet. Make sure these vents are open and clear of debris.
Install a dehumidifier to reduce moisture in your attic especially if you do not have a method of natural moisture control, such as a window. Reducing moisture will help reduce humidity in the attic, lowering the overall temperature.
Install an exhaust fan in your roof. When combined with inlets in your soffits, an exhaust fan can encourage air up through the attic and out of the house, providing you with a natural cooling system.
Place a radiant barrier in the space between the roof and the attic. When heat is absorbed by the roof, it causes the heat to radiate into the space below (the attic). A radiant barrier made of foil batting, Mylar sheets or a latex-based roof paint can reflect that heat back out of the house and away from the attic.