OK, this concept is somewhat hard to explain. I will give it a try, but I am not sure I can get it across in a blog post. Here we go:
Paint is irreversible: therefore a painter must get it right a first time, or otherwise face extensive fix up work. The more experience the painter gets, the more confident a painter becomes. It is better to make a (small) mistake than restrict yourself to making timid and boring paintings.

The starry night, Vincent van Gogh, 1889, oil on canvas, 74x92cm, MoMa, New York
I notice something similar in presentation design. Be confident as your design your slide in "analogue mode", scribbling on a piece of paper. Be confident to open the PowerPoint screen, delete all Microsoft bullets and start adding elements from your design: box, box box, align, arrow, etc. Make them big, bold, confident, but minimalist.
In this way you work faster, and slides come out more natural. It is all about confidence.
Maybe this post does a better job in explaining.