An app called Grammerly. You can use the free version. I have the paid version but the free one works great!
Readers are turned off if they have to struggle to read your work. Your storylines are wonderful and this may be what you need to keep readers.
Also, plan the characters, basically how the story will end. This will help you as you write each chapter.
For instance: Denise is kind of dizzy but well-meaning. She will be paired with Scott. Devin is the bad guy. He goes to jail at the end.
Keep writing!