The biggest breakthrough for me came a few years back... learning that failing is GOOD. As long as you do it fast, learn, adjust, move on, etc. Too many people let the fear of failing cripple them and it stops them from doing anything. Or they worry they're sales copy won't be good enough, or their product might tank... none of those things are bad as long as it happens swiftly, you know which bit went wrong (testing and tracking).
I used to have far more fails or "not very successful" things as I did successful ones. Now I still have fails because I dare to try things, but because the fails come and go quickly and things get adjusted... it looks like most of what I touch turns to gold.
This year I had some ball buster fails. In my offline experiments I had to fold a limited company! But it doesn't matter because those things happened quick and I learned from them.
I just keep in mind what I was told when I was doing telesales (cold calling). If one in ten calls gets a sale and that sale earns me $100, then every call that gets a "no" has earned me $10... and the call that gets me a yes does the same.
I need the fails to get to the successes.
So if fear of failing is holding anyone back. Slap yourself and realize... failing is good (if done right). Not failing by not doing gets you nowhere. So just damn well go for it. Pull the trigger, launch, try things, benefit from the failing when it happens.
Failing 9 times and having one success puts money in your bank. Not even trying because "you might fail" puts nothing in your bank.