The most important component of your book is the cover
Two areas where your budget must not be squeezed, are the cover and copyediting/proofreading. Focusing on these will ensure that you have a book that is as commercial as it could possibly be.
Once your manuscript becomes a book it will have to sell in a very large and competitive marketplace. No matter where your audience is: Amazon, iBooks or independent book shops, your book cover is the gateway to sales.
Releasing a Philippa Gregory type novel? Have a Philippa Gregory cover style. Show that particular audience that your book is going to be right up their street.
Black Swan takes into account current market trends. Ignoring these could make your book stick out for all the wrong reasons. A great cover makes a book much easier to market, and will get the attention the book needs. Get the cover right and you’ll have a book that will sit comfortably alongside mainstream titles.