Failed pacing is a dangerous trap for any author to fall into. A story that gives too much detail will quickly become tedious, but taking things back out to compensate can leave the story feeling spare, even disorienting in its lack of definition. Read the books of great authors to find what they put in and what they leave out. Find how they transition their characters from one setting to another, where they squeeze in descriptions and how they so successfully leave some details to the imagination.
The best stories have a relentless purpose and never let it out of sight. The heightening conflict or question keeps the characters striving and the reader hooked to learn the result. When reading great authors, notice how they fill each word and sentence with purpose. Good writing has no useless words. Excellent writing efficiently layers purpose upon purpose using the same words. One sentence can describe a face, imply an emotional tone and foreshadow a conflict all at once.
Dialogue is another infamously tricky element of fiction writing. Fictional dialogue must be efficient and interesting yet ring true. Well-written dialogue does not actually copy the way real people talk, but it should seem to, because it extracts the essence of the intent, significance, emotion and expression of the way people talk in real life. When reading good writing, watch for the ways the author uses dialogue to heighten conflict and express characters' values and keep an eye out for the signals an author uses to distinguish different characters' voices without caricaturing them.
Perhaps the most important part of a story is the theme, the lesson or value the author expresses through the story. If plot, pacing and so on form the "how" of fiction, theme is the "why." Read with an eye to discerning not only what the theme is but also how different authors express their themes without being either too subtle or too heavy-handed. Follow the values different characters act on and how those actions and their results are calculated to reveal what the author believes about the values thus revealed.