I've been helping several clients to choose cover images for their books this week. These authors have either been re-branding existing books that haven't been selling very well... or been choosing images for brand new books that are about to be launched. As research shows that 74% of a reader's buying decision is based on a book cover alone, it's vital to get this right.

This means paying careful attention to:

* Your book title;

* The image on the front of your book;

* The colours used;

* The font used;

* The blurb on the back of your book;

* The testimonials you use on the book cover.

It pays to spend time making your Contents page sound as compelling as possible. Your very first sentence should also grab the reader by the collar, as should the rest of page 1.

To select the right cover for the front of a book, it's essential to do a little market research, and focus on your target readership. One of the authors I've been working with this week has written a fantasy book aimed at young adults.

His designer produced 18 book covers, which the author and his team all really liked. However, when I showed these same covers to my sixteen-year-old son and his friends, they said things like: "these look really boring", "I don't know what it's about" and "I wouldn't read it".

To get an idea of what did appeal to them, I instead showed them a random sample of 10 fantasy books on Amazon. I asked which they liked most and what they would read. They opted for book covers that to me seemed a bit basic, unsophisticated and even downright 'cheesy' - with characters in action scenes. However, the important thing here is that my opinion and aesthetics were irrelevant. Teenagers are the target readership for this book and these were the type of cover images they preferred.

'Crossover books' - book designed to appeal to both adults AND children - usually have two entirely different covers. The Harry Potter books do this, for example, as do the 'Northern Lights' books by Philip Pullman. Most books published globally will also have different covers, as every country will have different cultural references. The colour white may be associated with weddings and innocence in the UK; but in China it is associated with death and mourning.

For this reason, I always recommend that you do your market research first before you produce a book cover. Make sure you get feedback from your target audience on every aspect of your cover and what it means to them.

When choosing a cover image, it is also vital to consider what your long-term goals are for your book. A picture paints a thousand words. Every cover image therefore gives instant subliminal messages, based on a reader's associations.

Another of my non-fiction clients is about to publish a book to attract new clients for her pension planning business.

Here are a selection of some of acim  designs she has looked at:

1. A dinghy and a lifebelt image on the cover, to give a sense of drama and urgency to her message.

2. A solid oak tree with rotten roots to symbolise the state of most people's finances.

3. An empty glass jar, with the word 'pension' on the side, to illustrate the fact that most people's pension pots are empty.

4. A golden egg in a nest symbolising the notion of a golden nest egg.

5. A picture of the author on the front looking friendly and personable.

Each of these five images has its merits. However, they will each attract different types of readers. The author wishes to attract affluent middle class professionals who are already fairly financially stable, to her business. It therefore makes no sense to have images which suggest poverty or desperation such as the dinghy, the empty pension pot or the rotten tree. Instead, the golden nest egg is much more likely to appeal, as is the picture of the author on the front. However, if she wishes to sell her business in the future, or prefers to delegate consultancy to other partners in the business, then it is probably better not to have her photo on the cover.

Gold, on the other hand, always conveys a 'success' message to a reader. (Think about how many bestselling books have gold lettering on the cover for example.) The gold nest egg image instantly conveys that the book is 'special'; the gold lettering also suggests that the book is a bestseller. This image is therefore much more likely to appeal to her target readership.

It always pays to spend time on your book cover, to do your market research, and to have your cover professionally produced. I am constantly seeing amateurish books with clip art on the front, or images that simply aren't congruent with the target readership. That's why book 'make-overs' and re-branding can work miracles for book sales. If you don't believe me, try it for yourself. Simply set up a split-test with your book. Keep your old version live on Amazon or Kindle. Then, set up a new version with a different cover and title. I can guarantee, you will soon notice the difference.