Start writing somewhere
As a kid, I had a terrible time with tests, because I couldn't skip questions that didn't make sense. I struggle with the same thing when writing. I want to start at the beginning and write until the end. Unfortunately, that is not how inspiration works, at least not for me.
Like the plants in the picture below, finding a place to be rooted in a story doesn't have to be at the base of the story. The stump in the photo below is well over 20 feet tall, with various plants (possibly the tree itself) growing out of the top. The tree is shattered, but still sustains life.
In the same way, inspiration when it comes can seem like shards from various pieces of glassware. The pieces are all clumped together, but if I don't start writing some of them down, I'll never know what the stories are about. I won't be able to distinguish the plate story from the vase one. Not every idea turns into a story, but if I don't start writing none of my ideas turn into stories.
Before I start a story or poem, I sometimes have a few scenes or a theme in my head. These will not necessarily be at the beginning of the story. Sometimes I can write toward these moments by writing the build up to them, but often it makes more sense just to write the parts I know and figure out how they fit together later.
Other times, I'll sit down to free write. Usually, the first few to several hundred words have no inherent value as art. However, they serve as a trigger.
Even when I have an idea of where a new chapter, story, or poem, is going. The first few words will often be closer to an essay's introductory paragraph than a literary hook.
These introductory paragraphs have no place in the final product, but help me figure out where I am going. No one wants to read a story that starts off - A meets B. They talk, get angry, kiss and make up. Then after the whole story is summarized have a scene with A on his or her way to the grocery store. etc.
In editing, I cut off the explanatory bit. Also, likely the journey to the store.
The story starts:
A reaches for the last peach. Their hand brushes against B's. (A classic meet-cute, which I would probably never use, but apparently am in a sappy mood today).
The trick is not getting attached to the bit of free writing at the beginning, which often takes the place of planning. Or to be more accurate is a type of planning.
The same thing can be said for writing down the random scenes and characteristics which could eventually make up a story. I try to remind myself to get them down on paper and figure out afterward if they fit into a cohesive whole.
However, if I wait for that perfect beginning to come to me. I will likely never start.