Don't take it personally:
Your contact may be in a rush, busy with other things or just not in the right frame of mind right now to discuss what you are calling about. Suggest another time to speak.
Think about why the rejection happened:
Could you have been more prepared with some information or answers to their questions. Make a note of anything that came up that you weren't sure about and be ready for the next time that comes up.
Do the research and be prepared:
Whether it's knowledge about the solution you are selling or background information about the company you are talking to, do the research and be prepared to answer questions and counter objections.
Be polite:
No matter what, always be polite and courteous and back out of a call gracefully if needed. Then move on to the next one.