I have always wanted a macro lens to get those close up shots, but have convinced myself out of it. They are more expensive, take up more space in the bag, and can be a bit cumbersome to change lenses depending on the situation.
Anyhow, my wife purchased the Hoya Close Up Filters for me and I have to say they are a convenient middle point for taking macro shots. You can get a set of 3 filters that are 1x, 2x, and 4x. The ones I have are for 52mm thread diameter lenses so it works perfectly on my 50mm Nikon 1.8D lens.
Basically, it decreases the minimum focusing distance for you lens so that you can get closer to the object than you were able to before. I was able to get a lot closer to my test subjects at Christmas time and get some decent close up photos.
It does not get a 1:1 ratio so you will not be able to get your subject to be the same size in the photo as it is in real life, but it definitely can make it a couple magnitudes larger.