I don't think any tactics work for me.
But what I want is a nice square synopsis or lead-in to the book. I don't care who recommends it or how many stars or what people are tweeting. Tell me what the book is about and not why I should read it based on the opinions of others.
In the not so distant past (before getting ereader) the blurb was my first line of defense against buying the same book twice. I find re-reading about as much fun as watching the grass grow, no offense to those who enjoy it. I have been reading 200+ books a year for at least 50 years so I do not remember all of the titles dammit, and if I am going to buy a book I want it to last more than ten pages in before I remember all the details
But I don't think any blurb has made me buy a book. If it is by an author I like I will just buy it and an author I don't like I won't. Anything else, I will borrow it if possible or if strongly recommended by someone I know look at a page or two.
Basically I take a lot of blurbs with the same grain of salt as advertisements for bridges for sale.
Helen