Wheb doing revisions and looking at characters, there are several questions to ask yourself. One - Is this character necessary? I've done this and sometimes there are characters in my stories and thsoe of other writers I read who are not necessary to the story. This is particularly true of minor characters and those walk-one who may have one line or none. All characters in a story should affect the outcome of the story. If they don't why have them there taking space and words to be used to more advantate?
The second question - Are any of your characters stereotypes? Sometimes this is hard to determine. What distinguishes a stereotypical character from a real one is giving them distinctive traits. Make yoru teenager, nurse, policeman have something that distinguishes them from the character everyone knows.
Detail is a way of doing this. Details bring people and scenes to life. Too much detail stalls the story. Finding a balance takes careful revision. I just finished reading several books. One had so much detail about the characters and events that I found myself drifting away from the story. The material was well researched but did the writer have to put every detail into the scene. Another book sprinkled the details with the touch of a chef. I finished the book and realized I had learned quite a bit about a particular era that I did in the first book with it's plethora of information.
So look at those descriptive passages and see what can be trimmed. Will make for a stronger book and keep the reader from yawning.