Your existing switches are often times ready to be upgraded to 2008 NEMA rated Decora switches. These switches are safer and often more attractive. These switches also come with motion and dimmer features. 1. Turn the power off. 2. Remove the two cover screws to remove cover plate and expose switch.   3.Remove the two 8/32 screws holding in the switch.   4. Unscrew one terminal on the old switch and take wire from terminal, attach wire to one side of new switch and tighten screw. 5. Unscrew the other terminal on old switch,  take wire from old switch to new switch and tighten new switch 6. Tuck the two wires from the switch into opposite corners, often times this step will save you time in the next step. 7. Push switch back into box minding the two tucked wires and any other wires in box. 8. Fasten two 8/32 screws to top and bottom of switch. Attempt to keep the top and bottom pushed to same side as you tighten it doesnt have to be super tight just flush. 9. Attach the cover plate and fasten the two cover screws. Doesnt have to be very tight just snug. 10. The most important thing to remember is always make sure the power is off at the panel.