I found this checklist on Goodreads and thought it might be helpful.

Does any part of the story drag?
Are there parts that you skipped to get to ‘the good part’?
Do I over-inform (info-dump) anywhere?
Did you understand every phrase/term I used?
Does one scene lead logically into the next?
Do the scenes flow smoothly from one action to the next, or did they jump as though something was skipped?
Is there enough downtime between intense scenes to allow it to build to the next?
Can you see every action clearly while reading?
If you went there in real life, would you recognize the places?
Did you have to reread any part of the action sequences to understand who was doing what?
Does the Dialogue sound realistic for the individual characters?
Could you see what the characters were doing while talking?
Could you see where the characters were while talking?
Could you see what each character looked like clearly?
Do their actions and reactions seem logical and realistic?
Could you feel the emotions between the characters?
Does the story stay focused on my main character?
Were any of my characters too much of a jerk or too aggressive?
Were any of my characters whiny, wimpy, or overly dramatic?
Are any of my characters too stereotypical?
Who did you like best and WHY?
Who did you hate and WHY?
Who got on your nerves and WHY?
Do any of the characters get in the way of the STORY?

Hope it helps!

And… not applicable to my fiction, but possibly helpful to other authors:-
Do any of the love scenes seem overly cliché?
Were the love scenes too fast, too slow, or too frequent?
Not applicable to my books: Did you have to reread any part of the love scenes to understand who was doing what?
Did any action in the love scene make you cringe?
Did it make you hot?