Fear will definitely hinder you from achieving whatever it is you're looking to do in your real estate business if you don't learn how to use that energy positively.
When I got started I feared putting out signs for my marketing, talking to sellers, spending money that I might not get back, worrying about people not wanting to sell me their home because of my skin color, not having the cash on hand to buy it, not pulling up to the house in a luxury car, etc, etc, etc...
All these things are just inside your head. Even if some of your fears do hold some weight...who cares!!!! For those things that do hold weight, there are plenty more that don't.
Until I was able to grasp that mentality NOTHING, and I mean NOTHING happened for me in my business. NOTHING but heartache, disappointment, and self doubt.
Get educated, take action, and tweak. The journey from where your are now to where you're trying to go is beautiful if you just take the leap.
You will never know everything you need to know. The only way you're going to learn is by getting yourself out there and making mistakes.