So here’s the thing. Creating art is a multi-step process.
First, you have to stop imagining and start doing. You have to scale that wall of fear that exists between the perfect piece in your mind, versus the piece (often beyond control) that will appear on the canvas.
Then, when you’ve gotten your material and your fear in hand, you need to demonstrate some patience. Yes, you have this urge to see how the final piece will look, but you know that the look you want can not be achieved until you wait for certain layers to dry.
Finally, you have to prove your attention to detail. The under layers are dry, the fear has been overcome and all that remains is your ability to pain stakingly recreate what you had imagined.
And then the art unravels and discovers itself to you. Then, as you near completion you realize, it has become so much more than what you had imagined.