DEAR CRABBIT: what if I can't afford professional editing?

From a blog comment:

Dear Crabbit,
It would be great if you did a post on the best things we can do if we can't afford a full-editing service, Nicola. I'm on a strict family income and spending on my writing just can't take centre stage. I can save and build some money to use, and would love to know the best way to spend it to get the best advice for my work. I can see how important outside proof reading and editing can be, so I want to get it right with my limited resources!

What does a proof-reader do?

What does a proof-reader do? You might think it's obvious: finds typos. And that's true. But it is also more complicated and more technical than that. After all, while some typos are clearly typos, others are stylistic traits and others are not typos at all but do require consistency.

Let me list some of the things my expert proof-reader found in Dear Agent (coming on Aug 10th!):

• Places where I'd got a very slightly different wording in the contents from the actual wording in the heading, because I'd changed my mind about the heading but not the contents list.
• I'd used the word blind-folded with a hyphen twice and without twice - the examples were far apart and to notice I'd have to remember to write down every single word that could have two forms as I came to them, so that I could check each one. There are LOADS of words that can be hyphenated or not, equally correctly, but you should do it the same each time.
• I use British spellings (eg realised not realized) but sometimes my computer auto-Americanises - my proof-reader had to notice.
• There were some things the meaning of which she wanted to check, because she wasn't sure it would be clear to everyone - this is a crucial task for a proof-reader and requires intelligence.
• She noticed a couple of bolds or italics which she questioned.
• She noticed that I seemed to have contradicted myself at one point. I hadn't, but I agreed it wasn't clear, so I adjusted.
• I'd capitalised something in one place but not another.

Other things a proof-reader must notice:

• I might have used curly quotes in one place and straight ones in another.
• Spelling and punctuation errors, of course.
• Wrong layout or line-spacing.*
• Inconsistent font/size in headings.
• Places where headings appear at the bottom of a page, or other uglinesses of layout.

[*Edited to add: layout requirements are different between ebooks and print books. The proof-reader would be told which he or she is doing, but would usually be required to be proofing according to print requirements, which means layout is for a page view and must avoid widows and orphans. Then it would be the job of the formatter to alter to suit the ebook format.

For example, too much white space is a nightmare in some ebook formats. And, as Dan points out in the comments below, widows and orphans are irrelevant because each reader/device can be set up differently. When we read ebooks, we have to accept that sometimes a heading, for example, will appear at the bottom of the "page", ie screen.

I told my proof-reader to ignore widows and orphans and line spacing. I then put in my instructions for the formatter, and I always give her discretion about line spacing, within reason. The formatter is not only a highly expert ebook formatter, using full html, but she was also a trained type-setter. So, I have all bases covered! And there will doubtless still be something that slips through!)]

It's a skilled task. It requires patience, knowledge of correct and varied uses, and a very meticulous way of working. 

The fact that my proof-reader for Dear Agent was my sister probably adds to the pressure!