Make sure your skin is free from make up and walk out to the sunlight..
If your face turns red, that's mean you have a cool skin tone. You may choose porcelain or ivory foundation. If your face turns yellowish, tan or dark, that's mean you have a warm skin tone. You may choose yellow base foundation such as golden or honey..
***Tips credit to 'EH Magazine' Nov 2010 Edition - nota cantik corner