Max 20 keywords?
Now I am experimenting with giving not more than 20 keywords to each photos. It helps focusing on the most relevant points.
(now it has: aroma barbecue barbeque bbq beef budapest celebration christmas cooking december delicious dinner eat eating fat festive food fragrance fried fry frying gourmet holiday hot hungary lunch market meal meat outdoor pan pork roast roasted roasting sausage seasonal smoke smokey tasty unhealthy xmas)
* put in as many keywords as possible (so gather all possible hits?)
* or to adopt the idea of focusing only on the most relevant meanings and layers of your pics (and therefore losing some possible hit, but the remaining will be maybe more to the point, and converted into sales?)