I have worked with several writers whose primary challenge was taking the step of sitting down at their desk. Their anticipatory anxiety or other resistances create a mental barrier against taking the first step. Often they are entertaining an inaccurate and exaggerated estimate of the agony that will ensue if they write.
I love to swim but I dislike getting into the water due to the brief shock of the initial chilliness. I spend a good bit of time on the deck, contemplating and postponing my entry, but once I dive in and do a couple of laps, I’m plenty warm and I enjoybeing immersed. Writers who have difficulty starting often do fine once they have taken the plunge, and the challenge is to learn to set up one’s writing life to increase the odds of diving in.
Setting up a daily writing schedule and sticking to it is the best way to work with this