One of the hardest things to do is write to sell something. Unfortunately, it's often necessary. Even if you are not working for a company that requires you to write a hard sell, we still have to market things daily - every time we write a cover letter for a novel submission, or a resume for a new job, we are effectively trying to sell something. Indeed, when we make forum posts arguing a political point of view, or a blog post expounding the virtues of a particular book - that we're secretly hoping people will buy through our Amazon affiliate link - we're writing to sell.

Writing to sell works best when you are genuinely impassioned about the thing you are selling. Sometimes, of course, we are hired to write a sales-pitch for a product we couldn't care less about. In these cases, we should imagine the product is something we care about. If you're selling a set of good-quality chefs knives, and your standard method of cooking is to bung some slop in a microwave you're not going to care that much. So imagine those knives are tools to do something you do care about. Let's say you are an avid fisher. Pretend the knives are the kind of fantastic fishing equipment you dream about. Get a feeling of real enthusiasm behind you, that you can draw on for your pitch.

Don't try and sell mediocre products. You devalue yourself - if someone buys a book because you recommend it, and they hate it, they won't ever buy another book from you again. Equally, if you flog a set of shoddy knives to all your friends and family, the next marketing program you sign up for, nobody is going to listen to you.

But assuming you have something that you really like, you want to sell, and you are sure people will appreciate, you now you have to convince them to buy it.

• Include Hard Data - This means author's name, size of hard-drive, type of steel, vintage date, flavour, PC or Mac, price, measurements, clothing size, whatever. The most basic information someone needs to know if its going to work for them.
• Avoid hyperbole. We are all desensitised to the kind of ads that have WILL CHANGE YOUR LIFE! surrounded by flashy stars with words like 'bargain' in. The modern consumer is bombarded with loud voices, flashy adverts, and unsustainable promises. Any product that tries this will fail, unless its aimed at the lowest common denominator and/or has a mega million budget to get the message everywhere.
• Make sustainable promises in the language of your audience. Let's say you were selling a book about web standards to a bunch of freelance web designers. You can promise them it will solve their compatibility issues, their 'spaghetti code' issues, and make them work more efficiently. These are things that web designers care about, and that knowing web standards can solve.
• Identify the problem your product solves. People buy for a number of reasons, but basically it comes down to solving a problem. That problem might be a made-up one, such as perceived social status, which can be 'solved' by driving a flashy sports car. Or it might be a really important problem, like a health issue. It may even be a problem where they need something entertaining to do that evening. Tell people how your product can make that problem go away, whether it's a flashy car (the best in your neighborhood), an alternative therapy (try acupuncture for a good night's sleep), or a great movie (Go see The Simpsons, it frikkin' rules!)
• Add human interest. Depending on how long your pitch is, you may be limited to ten words or ten pages. If you have space, draw in human interest stories. People are fascinated by themselves, they like hearing success stories, and they like hearing stories where they can empathise with someone.
• Follow the Rule of Three.
• Don't use high-falutin' language. Although you can use scientific terms and explanations to give something credibility, you should try and avoid sounding like a text-book. Keep it simple, chatty and informative.
• Don't use language you're not comfortable with. Trying to trick people into thinking you come from the ghetto when you don't will just make you look foolish.