No one enjoys writing blurbs. No one. Especially for a new author, blurbs are incredibly difficult. Take a look at the Hunger Games blurb above. There are some really good points and some things I would personally change. The first thing any reader should notice in a good blurb is the atmosphere. This one is easy to detect: desperation. The kill or be killed line is flawless.
The goal of a blurb is really to convey just a few basic things: genre, atmosphere, and the very basics of the plot. Does the Hunger Games blurb do these things? You bet. The genre is clearly dystopian. "A dark vision of the near future" sets that up well. The "certain death" and "kill or be killed" lines establish atmosphere. The general plot is very basic and all you need to know. A bunch of kids are forced to kill each other in an arena for the amusement of others. We don't need to know about Katniss and the love triangle and all that other stuff that happens. We will find that out within the first few chapters of the book anyways.
What should you never put in a blurb? Detailed plot points. More than a single line about a character. The actual name of the genre (i.e. don't write the word fantasy in your fantasy novel's blurb). A reference to other books or authors.
Since I gave an example of a great blurb, here's a bad one. I'm just making this up:
The Hunger Games tells the story of Katniss Everdeen, a love-struck teenager who volunteers to take her younger sister's place in a brutal annual event known as The Hunger Games. Will Katniss be strong enough to survive? Or will her conflicted heart be her undoing?
Many, many things should be obviously bad about that blurb. Too many adjectives. Too much plot. Two genres established. Is it romance? Is it action? Not enough dystopia. Not enough desperation. No epic notion of grandeur. Take a fresh look at your own blurbs and see where you can improve.
A few more pointers: never publish your first blurb. Write and rewrite that sucker at least a dozen times. Run it by 20 or 30 people to get their thoughts. After they read the blurb, ask them to predict the main plot of the book. If they miss the mark by a lot, you have more work to do. If they hit it spot on, you are giving too much away. You need a balance between mystery and just giving it away.
Should you put quotes from other authors on your back cover? Absolutely! Send your book around to authors in your genre you know and see if they will give you a review. Grab a line and slap it on the back. That can be wonderful for potential book sales.
Check out this back cover from Gone Girl:
Even though the back cover is just a list of quotes (inside panel has the actual blurb), the potential reader still gets almost all of the pertinent information. All of the words like terrifying and menacing let you know exactly what kind of thriller this is. When I talk about establishing an atmosphere for a novel with a blurb, this is what I mean. Nothing says dark thriller quite like "wickedly clever."