Once you have believable characters for your story and you have a great plot, you have to tell the story.  I like to call it painting pictures with words. Your readers need to see the story taking place the way you do. If you are writing a scene that takes place in a specific room like a kitchen, you could just write: Bob walked into the kitchen. He was angry. His wife Kelly was washing dishes. She wasn't happy.

Those are two very simple sentences. If you wanted to improve them you could write. Bob stomped into the kitchen frowning. His wife Kelly stood in front of the double sink with a wet cloth in one hand and a plate in the other. She stared out the window above the sink. Her face was drawn and tense. She hated the tiny little space she stood in. Her appliances were old and the counters were white subways tiles with loose and missing grout. The floor was faded yellow linoleum. 

Just adding a few descriptive words and phrases, I've now communicated that Bob was angry as he walking into the kitchen. I've also shown you that Kelly was washing the dishes, by telling you what was in her hands, and I've given you some idea of what the kitchen looks like.

From the added phrases and words, I painted a picture that helps the reader visualize the situation. I didn't go into extensive details like where the appliances are sitting. Most people will imagine a kitchen they have seen themselves, but they will see it with white subway tile counters, yellow linoleum floors, and older appliances. If you give too many details, you may bore your reader and we don't want that.

You also need to give descriptions of the characters, clothing, hairstyles, and expressions. Looking at the original scene I wrote, we have no idea what Bob or Kelly look like.  To give the reader a better idea of who we are talking about, I could write: Bob's plaid shirt and tan pants hung off his too thin body as he stomped into the kitchen frowning and rubbing his nearly bald head. He hated what they had become. His wife Kelly wore the same type of dress every day, a dress with small multi-colored flowers printed on the fabric. Her thining hair hung down her back in a single braid with a few wisps of hair clinging to her damps face. She stood in front of the double sink with a wet cloth in one hand and a plate in the other. She stared out the window above the sink. Her face was drawn and tense. She hated the tiny little space she stood in. Her appliances were old and the counters were white subways tiles with loose and missing grout. The floor was faded yellow linoleum. 

Now you have an idea of what the characters look like as well. We took a few simple sentences and turned them into a descriptive passage.