I've recently found a great keywording tool - it allows you to search for similar images and extract the consolidated keywords from images you select. Using this, I've been able to find a few obvious extra keywords. For example, my best-selling image at the moment is:
Previously, I'd used the following keywords to describe it:
- Deer, Antler, Stag, Wildlife, Nature, Animal, Mammal, Autumn, outdoors, wild
But now, I've added: hunt, doe, buck, male, forest, antlers, brown, fall, game, grass,trees, woods, season, hunting, park, large, roebuck
Time will tell how useful it's been, but although a tedious job, it's a no-brainer to give it a go.
p.s. On Fotolia*, they won't allow you to update the keywords after the first submission, to "avoid keyword spamming". A shame, frankly!