Flowers are another very popular subject in popular photography, and quite addicting, actually. There are just a couple of easy-to-remember tricks to get some very nice shots even if you (like me) don't have a macro lens. (To clarify: these are in no way macro pictures, but try getting even relatively close to a flower with basics settings and you'll see what I mean)
I arrived at this first picture just before sunset, although clearly you would not know that by looking at it because the flash had a mind to pop itself up at the last second.
So, here's what you do. Select the camera mode symbolized by a flower (easy to remember, see?); depending on your camera, it will be located on the little wheel, or inside a menu, or maybe you have a ninety-thousand-dollar camera and there is no flower option because you are a genius.
So, select flower mode. It allows you to focus at a closer range than you normally could in other modes (without a macro lens). When you focus, it's possible the on-board flash will pop up automatically to aid exposure (unless you threw down money on a big-time separate flash); if it doesn't, click it up anyway. It will accomplish a couple of things:
It will allow the flower to show up brilliantly, even though you are likely in sunlight - it doesn't hurt a thing. It will also likely render the background dark, if not almost black, creating a very nice effect that, in photo editing, requires lots of layering and masking otherwise.
The flash also allows a quick shutter speed, which freezes the flower if there's a slight breeze and allows for a nice, sharp photo. Really, you can't go wrong!