Hi Nathan.

Thanks for your question, and you're right in your assumption that it depends on several factors, so there is no right answer. The usual point brought up on stock forums is quality vs quantity. I'd like to say quality is more important, but that's not entirely true. Some of my better photos have never sold at all, while some mediocre pics have sold quite well.

Figuring out demand isn't easy as most stock sites don't release exact figures on customer searches, but there are ways of gauging demand, and it's easy to compare this with the supply. I took this a step further when doing research and created a spreadsheet which factored in things like supply, ease of shooting, google trends, etc, ultimately awarding scores for various topics.

As you might expect, stock cliches scored very low. Things such as "hands shaking" are in copious supply, as are background textures, skies, sunsets. The highest scoring topics were always trending topics, be it fidget spinners, or a new diet fad. Using your imagination and creativity, you can extend this to things like scientific discoveries, or following the political zeitgeist. This all requires effort, but the potential rewards are highest using this approach.

You can also take a more passive approach, and still earn respectable money, just by uploading regularly. Efficiency and opportunity are key for me. Take a camera everywhere, even if it means buying a cheap backup and leaving it in your cars glove box. Then simply knowing what could sell will help. A monument or landmark, absolutely. Animals, for sure, especially if you know the exact breed. Same with flowers.

The most important thing is sticking with it. You can refine your approach as time goes on.