1. The Lens
There are several good lens options out there for macro photography. You could use extension tubes combined with a normal lens, which gives you some magnification; or, even better, you could reverse a normal lens which, when combined with extension tubes, gives even more magnification.
The most convenient and flexible option though, especially for a beginner within macro photography, is to get a dedicated macro lens.
The most popular models come in focal lengths between 90-105 mm, and have a 1:1 magnification ratio. There are also shorter focal lengths such as 50 or 60mm, but these have shorter working distances, which means you have to get very close to your subject and risk scaring it away. 1:1 magnification means that, when you focus as closely as possible, your subject is as big on the sensor as it is in real life. So if you have a full frame sensor of 36×24 mm, it means that any insect you want to shoot that is 36mm long just about fits in your picture.
If you use an APS-C or Micro Four Thirds camera, you will get your subject magnified even more at 1x, as the sensor is smaller. These normal, 1:1 macro lenses are made by most major brands, such as Sigma’s 105mm, Canon’s 100 mm, Nikon’s 105mm, Samyang’s 100mm, Tamron’s legendary 90mm, Sony’s 90mm and Tokina’s 100mm. They cost around $400-$1,000, and they are all sharp and a great value for the money.
Many of these lenses have image stabilization, which is a good thing, as it makes composition a lot easier. Have a look at reviews and buy one that you like. You can’t go wrong with a ~100mm 1:1 macro lens—image quality wise, most of them produce comparable results.
2. Location and weather
Some of the most interesting subjects to photograph with a macro lens are small bugs and insects. Flowers and various plants are also fun, and can often make interesting abstract images. The locations that offer the most to a macro photographer are, in my experience, places with lots of flowers and plants. Botanical gardens are especially great.
The best time to go out if you want to shoot bugs and insects is whenever the outside temperature is about 17°C (63°F) or warmer, as insects tend to be more active when it is warm outside. On the other hand, if you are good at finding insects where they rest (I have personally found this very hard), they hold still longer when it is cold. Some macro photographers like to go out on early summer mornings to catch the insects when they’re not quite so active.
Overcast weather is usually better than sunny weather, as it gives a softer light.