Alexandra Bortkiewicz is the director of photography at Alamy, an international stock image library with in excess of 20 million images in its collection. She explains, as part of our 11 Tips for 2011 series, how to get the most from your stock photography.

Shooting for stock is potentially a great way to generate additional income but, as with any other money-generating initiative, you need to research it to make it work. I always recommend looking at current ads, in print and online, to see what’s popular, and at fashion spreads in magazines for creative ideas, especially for travel, vacation and lifestyle shots. Keeping abreast of trends helps ensure your images don’t date too quickly, and therefore have a decent shelf life. The right image can sell over and over again.

Think carefully about the subject of your images, both literally and conceptually. Images that illustrate ideas such as communication, escape and the future are always in demand, while concepts such as recession and economic hardship are particularly popular right now, indicative of the sign of the times. Social and economic trends can be useful guidelines for your work, and I don’t just mean following the news headlines – the British population is ageing, for example, so concepts such as retirement and old age are becoming increasingly popular. It’s worth digging into these trends for less obvious ideas too. The over-fifties start more businesses than any other age group, for example, so images of older people at work are just as relevant as other shots, and probably much less common.

Stock photography encompasses a broad range of subject matter, all of which has potential to sell, but lifestyle imagery generates the most demand, followed by concepts, food, landscapes and cut-outs, then specialist subjects like agriculture, sports and so on. Developing a niche and a distinctive style can be rewarding, but if you’re clever, you’ll create images that sell in more than one market. One portfolio I viewed earlier this year featured food images shot with a kaleidoscope effect, which could work both literally and on a conceptual or abstract level.

Stock images don’t need to have been created specifically for stock sales – images with a narrative can appeal for your portfolio and website too, and you should always consider reselling personal and assignment projects. But if you’re selecting images from your existing portfolio, think through your aesthetic. Images that work on an emotional, visceral, conceptual, or striking visual level are always popular, and generic images sell well because they allow the client to introduce their own brand. Similarly abstract, graphic images are also popular, because they can be used as backgrounds for products or text. Images with a Facebook, snapshot sensibility have become popular in the UK, particularly in ads, but don’t be fooled by the relaxed style – you need to be rigorous about permissions and ensure your images have model releases, and that you have retained the copyright on anything shot on assignment.

This article, and the other 10 tips from our panel of experts [to be published each day until 31 January], were first appeared in BJP's January issue, published on 05 January 2011. It's still available for purchase from your nearest newsagent until 02 February 2011. To find your nearest newsagent, check our Store Finder.