Flash back to art school.
I had drawn before so why couldn't I make "this" work? "This" was whatever skill or project I was working on at the time. All I had to do was draw what I saw. It was right there in front of me, right? Easy right? Not really. I was learning new skills, new ways of seeing, drawing, and rendering.
So I took myself aside and had a little conversation.
Have you ever done this before?
Then why are you beating yourself up for not getting it right(perfect) the first time? It takes practice. Take a look at what's working and what isn't. Adjust and try again.