Matt Laur , Nov 18, 2009; 03:40 p.m.
What sort of camera? What sort of macro lens?
What is the image supposed to look like? Meaning, are you trying to include them item (like a watch) in scene with other objects, or a visible background... or are you going for close-up detail elements? When you say jewelry, do you mean rings, or large necklaces?
How are you lighting the scene? What sort of surface are you shooting on?
No, you don't need a meter - though it will help you get there faster. At least with table-top product shooting, you have time to shoot, then check the image's histogram so that you can see whether you're blocking up the shadows, or clipping the highlights. Shoot an 18% grey card in the same light, and look for a spike right in the middle of the histogram.
Distance between the camera and the subject will impact perspective distorition, depth of field, and the amount of background that's visible. And, of course, how much of the frame is filled with your subject. Can't provide specific pointers until you explain a bit more about what it is you're trying to accomplish, and using which tools.