Macro photography is accomplished by using what's called a macro lens, or with lens extension tubes. Macro lenses are specialized to shoot objects very close up, great for capturing small things or details. They are also used to create special effects, by taking example of their extremely shallow depth of field. Similarly, extension tubes are essentially ring like objects that attach to the end of your lens, moving the glass lens element away from the camera body, thus creating a magnifying effect whereas the lens is able to shoot very close to the subject, just like a macro lens. Having a macro lens is great; however, if you want a versatile solution, for a lower cost, check out lens extension tubes. Here are some quick tips.
1. Use a higher shutter speed. Remember, when you are focusing on a small object, as small as a wildflower the size of a silver dollar, every camera movement is exaggerated. Slow shutter speeds and an unsteady hand will result in motion blur, out of focus subjects, and/or less control over your creative vision. For example, I wouldn't advise handheld shooting at a shutter speed slower than 1/160 of a second, unless you have a tripod, or you are in a very bright environment. It's a handy trick, if you want to keep things easier.
2. Use a tripod. You'll find very quickly that the depth of field is very shallow. This means it will be harder to get the part of the subject you want correctly focused. A tripod can enable you to shoot with a higher aperture, thus more of the object will be in focus. Tripods are especially important if you are shooting in a low light environment. This will enable you to perfectly capture the image you're after.
3. Think outside the box. It's tempting to go and shoot a penny, at least for practice. But some really interesting macro photographs come from seeing an ordinary object in a different way. For example what if you photographed the zipper on a pair of blue jeans, the texture and color contrast would make for an awesome capture. Nature is especially incredible from a macro standpoint. Seeing things closer than you could with the human eye, can create beautiful and interesting compositions. If you've ever seen the series tv series called "Planet Earth," you'll know what i'm talking about.
4. Practice shooting macro at different apertures. When it comes to macro photography, the selective focus area is especially important. Sometimes you may want to draw the eye to an interesting aspect and leave everything else out of focus. For example, perhaps you're photographing a button on a shirt. You may want only the center, where the threads go thru the holes in focus. This effect would require a lower aperture (smaller number). Having the entire button in focus would require a higher aperture (bigger number).
Here's an example of macro photography, using lens extension tubes. These are two different angles, I shot of some Colorado Wildflowers, during a hike in the early morning. In real life, each were about the size of a silver dollar.
As with anything, the best way to learn the tricks is to practice on different subjects, with different camera settings, in different lighting environments. You can find macro lenses that shoot incredibly small objects like a single sprinkle, or macro lenses that shoot further out, perfect for filling up the frame with person's face.