Words are important you you as a writer. How do you choose the right ones? Let me count the ways. Actually I won't, just add a few things to be aware of.
Words are used in many ways by a writer and finding the ones that suit can be difficult. What the reader reads will be how he pictures your words, so you need to be selective. One thing you must consider is among your characters - Who is being viewed. You will need to know much about your character. What's his career? Choosing the right words to build a picture of a doctor, a lawyer or a car mechanic will be different.
Next you have to find the words to describe when he is. Different people react in many ways to the weather. Another is how old are they when your story takes place. A child reacts and needs different words from an adult.
Where do you find your characters. Are they at home, on the job or pursuing some other place. You need to find the right words to let the reacer know.
What are they doing? A sleeper is different from someone taking part in a sport. What are they feeling at this time? Emotions need the right words to make the reader believe.
What is the focus character noticing? How is he or she reacting? This is important and the wrong words will either mislead the reader or turn the reader off.
Once you know these things you need to arrange them so they make sense. This may take time, particularly with your first story but should become easier with practice.