I know the title of this question is too broad. But I think this is the apt title for my doubts.

I am a non-native speaker of English language. Even then I love to write in English whenever I get time. I have been given a task to write screenplay for a 30 minute English short film. Yes..it's not a big deal to write a story. But it is definitely a big deal to write a good story. I don't have a vast vocabulary. Whenever I write, I keep on using the same words again & again. I hate doing that. How can I improve my English & avoid using same words again & again?

I keep a journal everyday. I have a dictionary in my pocket every time. I learn new words whenever I get time. But the problem is I have a short memory. So I am not able to memorize every new word I learn. I don't get time to read books because of my hectic work.

It would be great if I get a few tips from a stranger.

Down voters can down vote as much as they want. Gracias.