Getting over Cold calling jitters.... HELP?

I recently started a job with a well known insurance company. We specialize in B2B sales. I have never done sales before but I feel I could prosper in this career. My only problem is getting in the door. I have this fear of going into a company and pursuing the business owner. What advice can you give me to over come this and get my business up and running. What did you guys do to help you. Thanks in advance.