I have encountered many people who on hearing that I'm a writer, reveal that they have a book that they've been working on for a while. I am often asked what is the right time to approach an agent, or how to go about getting their work published. Here is a summary of what I've learned so far.

First ask yourself why you are trying to write and publish a novel. Here are some reasons that I consider disastrous:

• You imagine that writing will make you money relatively easily.
• You imagine it will bring you respect and status.
• You imagine that you will be one of the lucky ones, and that your work will become an instant success and be read all over the world.

Writing is hard. Your ego will be bruised. People will ignore you. You may find yourself looking at work much worse than your own in print every day. If writing is not something that you are driven to do, I recommend finding another hobby with less potential for heartbreak.

Here are some reasons that I think are valid for writing a novel:

• You get up every day thinking of things you want to write.
• The act of writing is so satisfying to you that you'd rather do it than anything else.

In my experience, agents and publishers will not consider a new writer unless they have already proven that they can complete a manuscript, as many people cannot.

You must finish your work completely before you send it.

This may well mean several years of continual effort on a single project, with absolutely no promise of public interest at the end. I strongly recommend that you do not even start unless the act of writing is something that you adore for its own sake.

Before you start thinking of writing a novel, I recommend learning to write first. You may think you know how already, but fiction is a very hard market. Make sure. Read books on writing. Attend classes. Good writing classes are priceless.

Having said that, it's my impression that writing classes vary significantly between institutions. I used the Gotham Writers' Workshop in New York to get started and found them excellent. However, surprisingly, almost everything I've seen or heard about university-run literary fiction classes has been negative.

The screenwriting community appears to have a far more honest and disciplined approach to storytelling than the literary fiction community. I'd recommend learning everything you can about screenplays.

The product of your imagination may seem unique and special to you, but that is no guarantee that it will be to others. Always show your work to a trusted reader before you try showing it to a professional.

By trusted reader, I do not mean someone who will tell you that they liked your work. Neither do I mean someone who will laugh at it. I mean someone who will give you a balanced, impartial assessment of its readability. Choose someone whose intelligence you respect, and who is not beyond the hard task of telling you where you have made mistakes.

Better than a single trusted reader is a group of them. In my opinion, writers groups are invaluable. The more serious the people who comprise them are, the better the quality of response you will receive. Do not worry that someone is going to steal your idea. In fiction, I have never known this to happen.

However, it is worth noting that theft of ideas is rife in the film world. Do not let anyone from the movie industry look at your work without consulting an agent first. I have learned this to my cost.

All my experience to date has suggested that agents and publishers have little patience for imperfect manuscripts. Learn how to present a manuscript properly. Check the spelling. Learn good grammar and apply it. Anything that they can find wrong with your work will be an excuse for them to ignore it.

Some agents and publishers never reply. Others reply after incredibly long periods of time. Many agents and publishers will not do your work justice once it is sitting in front of them, simply because they have too much other work to do.

It may be decades before you get published, even if you are the finest writer on Earth. For this reason, people will tell you 'don't quit your day job'. I quit my day job anyway, and it has been a lot of fun. However I would only recommend it as a strategy if you can live rent free with no income for an indefinite period of time.

The responses I've received from agents and publishers have often varied wildly in their remarks about my work. If anyone has advice for you about what to do to your work, take it with a pinch of salt. If anyone tells you that if you adapt your book in a specific way that they then might consider it for publication, remember that this is not a promise. Only adapt your own work if it suits your purposes to do so. The advice of a well selected writers' group will often be more consistent and considered.

If you are one of the few people out there who are genuinely suited to writing as a career, you must stick with it. Unless we all keep trying, only established writers will ever get published. And established writers can write crap and have it accepted. Committed, informed, disciplined, aspiring writers are what prevent the science fiction genre from sliding any futher into decay.