A final word on Blurbs

You Should:

See if you can get some Quotes from well-known authors. Some  will refuse you, but if one responds it will be worth it. The same applies to famous people reviewing your book because you can add their quotes to your book description. Quoting individual authors instead of publications will give you a much better click-through rate and that is what you want.

If you have won awards for your writing including that too.

Pick the best 5-star review and add that to your description.

You Should Not:-

Never give away the end of the story. In fact, be sparing in your actual description; make the reader curious, but be sure not to give away too much plot.  Avoid clichés and overused phrases like "in a world of..." which always makes me want to add the words "Myth and Magic"....because I heard it so many times while watching Merlin on tv.

Comparing yourself with other author can raise the wrong expectations with your readers. It is not very wise to call  yourself the "new Stephen King" or advertise your book as the 

"next Fifty Shades of Grey."