I'm sure that all of you, my lovely readers and fellow writers, know how to use apostrophes correctly. But since I'm always being driven to distraction by their frequent misuse — in books, on signs, in promotional literature — I decided I'd write this: my potted guide to the apostrophe. If you know someone who struggles with the little blighters then why not print out a copy and staple it to their head … er, I mean tape it to their computer screen.

The first thing you need to know about apostrophes is that they have two main uses: to indicate contraction, and to indicate possession. That sounds pretty abstract and not at all memorable, so here are some examples.

If you've been keeping up with the blog over the past few weeks then you may have noticed that I'm trying to give the ol' place a bit more structure (read: be more organised with my topics so I have at least some chance of posting regularly). The first Sunday of the month is when I reflect on personal matters; the second is for book recommendations; the third is for showcasing some of my own work; and the fourth – which is where we are now – is for musings on the art of writing. And not only that, but the related art of editing.

Those of you who are somewhat acquainted with me will know that when I'm not battling with Baby Smith or attempting to blog on a regular basis, I work full time as an editor. I haven't discussed this a great deal previously, but it strikes me that although I work in non-fiction, some of my experience might be of use to authors of all kinds. Which is why I'm now going to talk to you about proofreading – and more specifically, why today's writer needs it more than ever.

A proofreader is paid less than a copyeditor, and this is due to the level of artistic skill required. A good copyeditor should be thoroughly involved with the text. She should be able to suggest improvements to infelicitous sentences, eliminate word echoes, and highlight points at which the narrative fails to flow smoothly. She should notice when character X has brown eyes on one page and blue on another. While wider structural edits – plot, pace, character development – don't fall within her remit, she is very much in charge of the details. Consistency is the copyeditor's superpower.

A proofreader's job, on the other hand, is far more technical. The proofreader doesn't care about style (though proofreaders are often also copyeditors and, if you're lucky, may point out an awkward sentence or two the copyeditor missed). Instead, a good proofreader will flag up any misspellings, missing apostrophes and other punctuation/grammar issues; in short, anything that's an error rather than a stylistic choice. He will also – and this is the key point I'm getting to here – mark up problems with the layout and presentation of the text.

The role of the proofreader harks back to the days of typesetting, when the physical process of laying out the text for printing could introduce all kinds of errors, even after the book's content was signed off and completed. Nowadays, of course, everything is done on computer and (depending on the layout package being used) what you see is pretty much what you get. If your proofreader spots a mistake in your final laid-out-for-print manuscript, chances are it was there all along … except when it comes to ebooks.

In some ways, ebooks have taken us back to the error-prone days of manual print layout. Some ebooks have been scanned from printed texts, which is by no means a foolproof process and can result in a range of nonsensical word substitutions. Others contain characters that aren't recognised by one conversion program or another (ever seen a bunch of digits where there should be a dash or an accented character?). Even ebooks of new titles – which presumably haven't had to go through the trauma of being converted from an older format – often fall down when it comes to anything unusual, whether in content or in layout.

So here, finally, is my point. The proofreader's job is to view your text as your readers are going to view it – and with the rise of digital books, that means quite a few different ways. There's no point proofreading your print copy and leaving your ebooks to fend for themselves, because errors could have been introduced in the conversion process. Certainly the layout will be different in each format and needs checking. Yet despite the self-evidence of this statement, I can't count the number of ebooks I've read – produced by large, well-known publishers – in which the layout has been poor. Spacing and indentation of paragraphs, breaks before chapters, presentation of lists or columns: all these things can go wrong. You can't assume that anything other than simple block text (and sometimes not even that) can be poured into a new format without the need for tweaking.

So, indie authors, I beg you: proofread your ebooks. Get someone to read them in each of the final formats you want to make available. That way, you'll impress all of your audience, not just the part of it that likes print. Not only that, but you'll be ahead of many of your fellow authors – and quite a few established publishers as well.

By definition, every one of us exists in first-person present tense. Yet it's one of the most difficult tenses to write, and one in which it's very easy to make mistakes of logic. Perhaps this is because in some respects, the act of storytelling is in opposition to the act of simply being. Storytelling is invention, re-creation, the replacement of what is immediately around us with an artificial alternative. The storyteller is always a filter between us and the world, whereas true first-person present is essentially direct experience. Thus to write genuine first-person present, the author must become invisible – if you like, a filter that is entirely transparent.