Jennifer Laughran's "Ask the Agent" Tumblr is a valuable resource. She used to be a regular contributor to the Blue Boards and was tremendously helpful to many. She's blunt, but to my ears this is a plus.

Thank you, Anne, for sharing with us.  She has helpful tips.

FYI: Jenn Laughlan, a senior agent at Andrea Brown, published this Tumblr post yesterday on how to learn/improve PB writing. 
https://literaticat.tumblr.com/post/688217116054355968/how-do-your-clients-improve-their-writing-skills

Like Debbie said, if I had a connection with the agent through a conference or meeting, I led with that, otherwise I put it at the end. 

Hi!
I have a question about the format of a query letter.
I understand the "hook, book and cook" guidelines.  I have also seen people say it is important to say why you picked that agent to query.  Where does the "flattery" part come in, if at all?  Should WHY I chose to address this agent in particular come first or my hook?
Thank you!