Close all external doors and windows.
Have any broken windows or doors repaired by a professional to prevent air leakages.
Close window blinds and pull draperies shut to prohibit warm sunlight from shining in.
Place a floor fan near the staircase and turn on downstairs ceiling fans to propel the movement of cool air.
Open internal upstairs doors to allow for the adequate circulation of cool air.
Remove dust and dirt that may have accumulated in air registers.
Move objects that are blocking air registers. Rearrange furniture, if necessary, to keep the area directly in front of air registers clear.