From Self-Publishing Review:
By far, the weakest part of many self-published books is the synopsis found on Amazon and elsewhere. Worse than the cover, worse than the writing in the book itself, there are a lot of blurbs on Amazon that are pretty near atrocious. I include my own books in this category. Writing a decent blurb is an artform totally separate from writing a book.
Authors are also on record saying this is their least favorite part of the process. It can make you feel icky writing superlatives about your own book. At the same time, too many superlatives can literally be icky (“A work of genius” comes to mind). A good blurb needs to strike a balance between being informative, but not too informative, salesy, but not too salesy, while somehow coercing a stranger into spending money. It’s difficult, to say the least.
That said, there are some very common errors that show up time and again, and are pretty easy to change.
. . . .
- Make it 100-200 words at most. Use line breaks as well.
- Use bold and italics, such as for awards, or “#1 Bestseller,” if you’re so lucky.
- Remember to add genre keywords to your description (mystery, dystopia, thriller, and so on), but don’t overdo it.
- Use adjectives to describe a character. See: FSOG above. Christian Grey is “beautiful, brilliant, and intimidating.” We don’t need examples of this, adjectives are a good stand-in.
- Similarly, condense the plot as much as you can to its feeling, rather than a line by line retelling of action.
- Tell us about your lead character! A reader is looking to identify with a central protagonist.
- Write 200+ words, with no use of paragraph breaks. Stay away from one gigantic paragraph.
- Include spoilers – seems like a no-brainer, but a spoiler can sometimes be the most exciting part of a book so you’ll be tempted to put it in to tempt readers.
- Summarize the entire plot. See The Hunger Games blurb above. Basically: There’s this thing called the Hunger Games where people fight to the death. Katniss is selected to enter the games. That’s it. General is better, less is more.
- Be overly flattering of yourself. People are aware an indie book’s description is written by the author, so “The next Stephen King” is going to be transparent.
Link to the rest at Self-Publishing Review