Dialog is a shortcut for conveying details about your story. For example:
"I felt like my arms were going to fall off because I was carrying those heavy grocery bags.", said Alice as she flopped down onto the sofa.
I could have gone with something like this instead:
Alice started to pick up the bags that the clerk had filled with her groceries. This store is becoming so familiar these days - teenagers always seem to be hungry - but this beats getting dinner from some fast food place almost every night. Walking home, Alice went through her To-Do list - start dinner, get the mail, pay some bills tonight. Although Spring just started it warmed up very quickly, making everyone sluggish. Everyone except for those that ran their air conditioner at home. Electricity costs so much these days, plus the groceries are adding up too.
The sun was a little closer to the rooftops by the time Alice reached home. She heard the TV as she walked in, Bob is probably playing another game instead of doing his homework. Her arms ached as she sat down next to Bob. She was glad to see Bob - he's becoming a young man. Staring at Bob playing his game on TV, smiling a little as she drifted off to sleep.
Dialog is absent from the sample, yet it conveys a richer experience. Think about the world or scene you are trying to create and try to draw the reader in by telling the story as opposed to 'the facts' through dialog.
In terms of perfection when you use dialog, try to describe your character's typical traits in two or three words and drive their dialog and personality based on those words. For example, your character could be a 'born detective' so she could question everything, get easily distracted, and have a messy workspace. Your character's dialog would be more consistent without being boring because readers might be able to identify your character without you having to flag their dialog with the character's name.
Good luck with your story.