Life gets more interesting when you can get a 1:1 image size or closer. Photos of tiny details such as eyes on a fly, aphids on the petal of a flower, or reflections in a droplet of water are all examples of things that can only be photographed using a macro lens.
In all photography (including macro), as the lens gets closer to the subject , the image gets larger on the film (or image sensor) so the light reaching the sensor is lessened. The depth of field also becomes very shallow and to combat this, very small apertures are called for, which lessens the light even more. Both these things in combination mean that normal handheld exposures are usually out of the question. A tripod is needed for steadiness plus flash or reflector is needed in nearly every circumstance to give decent illumination.
Compact digital cameras often have a macro mode that lets you get close to the subject and get a good image but they usually end up with the lens very close to the subject, which is fine for flowers and static objects but can annoy insects and alter their behaviour and narrow depth of field is often an insurmountable issue.
In compact cameras look for the “macro” mode (usually a tulip symbol) and maybe also a “super macro” mode (tulip plus a ‘s’ is one way to show it). Often the flash is automatically disabled on compact digital cameras when working at the “super macro” distances, as the subject is too close for proper coverage. Make sure you have some other means of lighting in that case. Some digital cameras allow the in-body flash to be set at lower output in order to still trigger the slave flash but not produce too much light from the position of the camera.
Remember that aluminium foil, styro-foam and other bright
surfaces make good and inexpensive reflectors.
There's another little trick with digital cameras and closeups. If you take your photo using the camera's highest resolution setting (to maximise file size), and go in as close as your lens (and light) will allow, you can get the illusion of enlargement by cropping the picture on your computer (with image software) to create a full frame picture of the subject that retains sufficient quality suitable for printing a 6"x4" or for email/web use.
If you're serious about macro photography, you'll probably need to invest in specialised lenses, adaptors, ring-flashes and slaves.