What would I do if I had money?

[Richard]

So, I don't have any money, but supposing I did, what would be the best way to invest?

1) professional editing: £500 - £2000?
2) professional cover design £200 - £1000?
3) paid reviews (e.g Kirkus) £500
4) advertising design £1000?
5) advertising placement (?)

[Martin]

If you are serious about the success of your book consider it an investment.

1) Invest time and make sure your story is good. Listen to your beta readers.
2) Pay for professional editing. If you have a great story and bad spelling, grammar and punctuation people we pan it.
3) Pay for good cover art. People DO judge a book by it's cover.

Never PAY for reviews. Do a free book promotion to get reviews.

Be careful with advertising. Lots of scammers out there want your money.

[Assaph]

I'm with Marin.

Copy-editing / proofreading and a good cover are worth it (I'm going through a second round for my novel at the moment...).

Paid reviews are banned by Amazon, and advertising is good for market research but for actual sales (my experience, which was echoed by a few other writers).

[Richard]

You've both mentioned editing in terms of typos and grammar mistakes. Have you also had editorial advice at the story level?

[Martin]

I always get editorial advice.

It helps with plot holes, character issues and other things.

I get this help through a team of alpha and beta readers and my writers group. (As well as my editor) They are my target audience and their opinions matter to me more than someone I don't know.

I considered it. As part of the negotiations with that kind editor he reviewed a short story. He told me to change the race of the main character from black to white. "Because black folks don't read scifi." Screw that guy.

I don't pay for that kind of advice.

[Owen]

As most potential readers will see a book cover first, that is maybe the first thing I say to invest in. But a cover might eyes on your book (which is good) but it won't close a sale.

Professional editing is a judgment call. As much as reviewers mention typos and "grammar mistakes" (which are not uncommonly figments of their imagination), I've seen no strong evidence that they negatively effect sales, unless they are extremely bad. (I've seen book that sell very well with large numbers of typos.) Most authors should be able to get an acceptable level of proofing done without paying for it.

Professional editorial advice on things like plot, characterization, flow etc is also dicey. These things vary from reader to reader and genre to genre, and a professional editor may not have a better feel for them than you do. Some editors are gifted this way and can help a great deal -- but that may not translate into improved sales.

So, from what I have observed, readers are in fact pretty tolerant of what might generally be called both typos and editorial problems -- if they otherwise like the book (concept and character, primarily).

Kirkus review seem to have little if any positive effect and ads rarely pay off for new authors.

If I had a bottom line, it would be that none of those things are very likely to have a positive return on investment, unless a book is already selling well on it's own. Once a book starts selling, paid ads can be a benefit, but if a book is not selling, paid ads (or any of those other factors) are unlikely to make it sell.

[Martin]

I recommend Indie authors pay for two things:

Professional cover design.
Professional editing for spelling, grammar, punctuation.

Having your book feel and look professional doesn't mean your story will be great. It will keep readers from stubbing toes on commas and fall out of the story.

My $.02, YMMV