How many copies will I sell?

This is a question I'm often asked by authors, and I get it. Writing a book takes time, effort and persistence. You want to know whether your hard work is worth it and you can't help but think of all those famous, celebrated, rich authors who have sold a lot of books.

But - and don't groan - it's a tricky question to answer as it really depends on the book - the topic, the style, the price, the format, the audience and the sales channels. For example, a short, small, chatty book on mindfulness (a current trendy topic) priced at ￡8.99 placed in WH Smith Travel is likely to sell very well - thousands of copies in its first few months. A long, big, dense book on credit derivatives priced at ￡49.99 and mostly bought online won't sell as many copies - perhaps low hundreds if you're lucky. So the first point of order - ask this question only once the idea of your book is more fully formed. Ask your publisher: what are you forecasting to sell in the first year?

The ongoing performance of a book is also very important. The mindfulness book is much more likely to start big and fizzle out because although it got a promotional slot in WH Smith Travel, after that showcase, it might struggle against the myriad other books on mindfulness. The credit derivatives book doesn't have a big bang but it sells consistently on Amazon, perhaps for many years.

Yes, the mindfulness book might sell many more copies, but it's also much cheaper than the credit derivatives book. With some rough calculations, the credit derivatives author could earn as much as the mindfulness author over time. So if you have a niche book with a lower print run but a higher RRP, it's still possible that the total value of the sales is high. So it's not just about the number of copies. Ask your publisher: what will the book sell for and where?

Something else that you might not consider - a traditional publisher will have other opportunities for the book. eBook sales, rights deals, custom publishing, bespoke editions, third party licensees. Some of these might make you more money than the original paperback book and can be a regular source of income. Ask your publisher: what other sales channels are available?

So we've talked about sales, but what about what else the book might bring you? The book itself might not make you rich, but it could make you rich in other ways because being a published authors can bring new opportunities. Having a book, particularly with a traditional publisher, is a stamp of authority and credibility if you're willing to put in some effort to capitalise on the possibilities. Perhaps:

• it raises your profile in your field
• you can double your rates
• your speaker fees increase
• you're invited to more conferences
• your business or consultancy grows

All these are because of the book, even if it hasn't made a lot of money by itself. Now, this might not suit some authors who prefer to write and remain invisible but in the world of business and personal development where authors typically have a company or services associated with the book, this is a world of possibility.

So don't just think about the number of copies. Think about what a book might bring to you - reputation, influence, platform - and how you and your business could use this to your advantage.