no matter how long I beat the heavy whipping cream I can never get it right. please help,  how do I make my whipped cream to stay stiff.  

Sprinkle a packet of gelatin over 1/4 c cold water.  Once it softens, gently heat to dissolve the gelatin, then while still beating your whipped cream, pour dissolved gelatin in a steady, narrow stream into your whipped cream.  You will need to use it right away.  Hope that helps.

thank u guys for the tips,  will give it a try for sure!