Method 1) Close up lenses are better than you might think and are cheap, they screw onto your lens and enable you to get focus closer. Its exactly the same as putting reading glasses on. Get the correct size for your lenses filter thread.
Method 2) Increase the distance between the camera and lens either with Extension Tubes or Bellows. This increases quality over Method 1), but has the disadvantage of decoupling your lens from the camera so everything will be manual.
Method 3) Reversing ring, which mounts the lens backwards onto the camera. Again your in manual. Big advantage is they magnify more than most any other method, up to 4X life size with a standard lens. Again the reversing rings thread must match your lenses filter thread.
Method 4) Use the reversing from Method 3 by mounting a standard lens reversed onto an a mid telephoto lens with a back to back adapter. The advantage here is the telephoto lens is still coupled to the camera so metering and auto focus still work, its really a very high quality version of Method 1. Make sure the reversed lens is a shorter focal length than the lens you screw it onto or you'll get vignetting. Make sure the lens is supported, there'll be a lot of weight hanging on the lens mount. If you use a zoom, say a 70 - 200mm the magnification can be varied. I have taken professional pictures with this rig when I need to get closer than a dedicated Macro lens will allow.
All of these will be cheaper than a dedicated Macro lens and have the advantage of being able to focus with more magnification.
With all these methods depth of field will be tiny, so its small aperture and long shutter speeds. A flash helps, preferably a ring flash. Focusing is best done by moving the whole contraption backwards and forwards, the focus on the lens will have little effect.