Knowledge, practice and courage are your weapons against fear.
One person can step out of an airplane door at 10,000 feet without panic. Another can stand before an audience of 10,000 and give a speech without breaking a sweat. Another can up an offer by $10,000 without hesitation. Fears can be rational or irrational, but they are always personal and real. Everybody fears something.
To diminish a fear, you must first face it. The one hundredth skydive or speech or offer won't be as traumatic as the first. The best way to deal with first fears is through a combination of logic and bravery. Logically, most people who jump from planes or give speeches or make real estate offers don't die. They succeed through preparation. If your equipment is right and your training is complete, you are ready to jump. If your speech is carefully crafted and practiced, you are ready to speak. If you've done your research, you are ready to negotiate.
Nothing is stronger than your mind. Associate with confident people. You have seen many who have already done what you fear doing. Now do what they have done. Courage grows with action. Fear is learned and must be unlearned. After facing that fear, you will feel exhilarated. Without fear, there can be no courage. Fear provides the opportunity to be brave.