Aspiring authors often do something which is very kind of them, improves my day, but has no positive effect on their chances of publication whatsoever.

When you send in a submission and you enclose folders, document wallets, nice paper clips and sometimes even pretty ribbon, and then ask for your small SAE to be returned – I am the unworthy recipient of your lovely stationery. It's very kind, but it's not necessary! So, at the risk of depleting my stocks of these items (what am I saying?!), you only need your submission to be printed, double-spaced on white paper, held together with a very ordinary paper clip.

Don't worry about doing mock-ups of a book cover either. Publishers have their own procedures for deciding on covers, and authors rarely get the casting vote! Editors are trained never to judge a book by its cover – probably because they spend so much time reading manuscripts with no covers.

Don't include an extensive written analysis of where your book would sit in the current market (although of course you'll do your groundwork on the marketplace before writing). If agents and editors don't know this sort of information already, they're not doing their jobs right.

What is never a waste of time is to keep trying, keep writing and keep submitting. Remember, for a book to be taken on, the agent or publisher has to love it. And not everyone can love every book, so persevere and good luck!

Yours, Cressida