Keep Characters In Character
In any form of writing, you may have the need to write for a character - a child, mobster, a jockey - the list is endless.
Whoever your character is, give them credibility - broadly speaking.
Making your character sound as real as possible is the difference between 'not bad' and 'great'.
Find out how your character speaks. Use the words they use. Formulate sentences they way they do.
YouTube is your friend. Listen to interviews with real jockeys and use the way they speak to allow your jockey to live and breathe horse racing.
A jockey doesn't 'get on' a horse, they 'mount' it.
The horse doesn't 'run'. It 'gallops'.
It's not a 'finish line', it's a 'post'.
Improve your work by writing the way your character speaks, not the way you speak.
Remember: People have unbelievable bullshit detectors. You might be able to weasel your way past someone who doesn't understand horse racing, but you're going to be caught by a racing enthusiast.
Once you've finished writing, ask "is this how my character would speak?"