The best way is to continue. This is the difference between those who succeed in marketing and those who did not.
Secondly is to boost your power of persuasion.
Persuasion is the KEY to sales in marketing. Until you can persuade your clients to purchase, no sales will never be in view. I wrote a book on it, titled, '20 Secrets in Making Excellent Sales in Marketing': http://www.tripleclicks.com/14424670/detail.php?item=450353
. it will share with you my experience on the field and how i was able to boost myself when hit a rough path.
Your power of persuasion is increased if you believe that your products can change people's lives and add value to them. You will go all out to help them. Rejection will mean nothing to you.You will utilize it to build your sales margin. That was what i do and it works.
The other thing is having a vision board where you table your vision and what you want to achieve. This will boost your power of persuasion.
Lastly, is to never never give up till you get what you want in the business.Quitters never win and winners never quit.So which one are you?