Flowers are beautiful. Stock agencies can't get enough of pictures like these. That's why you should take as many of them as possible.
The best thing: they don't require much effort or skill on your part. Just make sure some part of the flower is in focus. It's best to choose a smaller aperture to achieve that effect (in this photo I chose F10 and the flower is in focus as you can see - the background doesn't matter). The rest will take care of itself.