The first Reader

"Handing over a manuscript to anyone is a traumatic experience.  What you need from a first reader is absolute honestly and it is surprising how often you don't get that from people.  Choose your first reader well."

There are things that your first reader needs to be.  A reader for a start.  My first reader reads a lot.  It is always the same person.   My husband Scotty.  
He is brutally honest and as invested in the books I write as I am.  
He works in service of the story and not my pitiful fragile ego.
.He reads the book all the way through, twice.  The second read is when he marks up the manuscript.
Then we have a "talk" and he gives me all his notes.  
These 'talks' always end up in yelling, screaming and tears, all mine.
As I said he is brutally honest and he will fight with me on points he thinks are important to lose or change and I will fight fiercely to keep.    
I have always ended up agreeing with him...evetually. 
He knows my characters as a reader which is much better than I do as a writer.  He knows when they are acting out of their established character.    He knows when the story is flabby and slow, or when there is too much exposition.   He knows when I am forcing my writing and when I am in the flow.    
He will confront me with the truth.  
 “In writing, you must kill all your darlings.”
William Faulkner,
I am never oblivious to the flaws in my books.  The problem is that most of the time I don't know how to fix it and I need another voice.  That's why I get all aggravated when he tells me to drown a lot of puppies.  I think it is really drastic.  He says get rid of it or fix it, your choice.
So If I really want to keep something then I have to figure out how - quick.