A thought about introducing character in your story

Where do you begin?
The answer is that it depends which isn’t really helpful at all.
So, forget that and maybe think about what the character is doing or saying and then pick a detail, perhaps of the face, maybe of his or her way of walking or running or even perhaps something quirky about the way they are dressed. It doesn’t matter so long as whatever detail you pick is relevant to the character, something that connects with the way that person will act and react in the story… An easy smile, say.
But if you choose that don’t just throw it in the mix and forget it. Use it. Is it because the person is amiable, people are drawn to him or her like a magnet. And what do they find when they get to know this character better? That’s the thing. Is the smile a mask or real…
Here is a bit of practice.
Why might you notice this man at the railway station?
Nothing about the man was exceptional. He was exactly the sort of person one’s eyes might glide over and retain not a single feature: neither too smart nor too shabby- he was wearing a Barbour-type three-quarter length coat.- even though the day was cold enough for scarf or gloves, he wore neither. His coat wasn’t done up though he did have his hands tucked into the pockets of his coat and while everyone else around him was studying the departures board in the train station, he wasn’t. He wasn’t looking at a phone or his watch either…
When he glanced at me, perhaps noticing my attention, his expression was bland but I saw dark rings under his eyes and his skin wasn’t city pale but weathered. A man who spent more time out of doors perhaps.
I wondered who in that crowd of commuters and travellers he was watching. I tried to follow the direction of his gaze but when after a mere moment I glanced back at him, he had gone.