Hi Jemimamoon,
Nice weight - even with the stray bubbles in the dome.
Looking forwarding to the other photos
For "best photo lighting" you could try constructing a "light tent" of some form but that's not easy without buying a proper piece of kit.
I usually just use a plain white background that does not show joins or creases. I then check for how much of the room, me and other "objects" are reflected in the dome and try to eliminate as many as possible by closing curtains or hanging up a screen of some kind. I always leave a single daylight source to let the camera do its auto-focus job.
Having got the basic setting, I go for shots without flash and with. But I let the camera pre-focus and then I stand between the daylight and the weight to get rid of much of the other refelctions before taking the shot. With the non-flash shots I sometimes find the reflections are too much but with the flash usually most of the unwanted stuff is killed off.
If there are room lights on - I switch them off. If it's dark anyway and I have to use artificial lighting (which is quite frequent in dear old England) I always use flash to get the best colour balance but I also use a halogen light for the stages up to pre-focus and then try with the lamp on and off.
When using flash, there can occasionally be too much glare bounced back from the white background - particularly troublesome for profile views or top views where the weight has a clear ground. By adjusting the distance between the background and the weight much of the flare is avoided. For the top view shots, I stand the weight on a clear plastic support giving about 3 inches clearance from a sheet of plain white paper.
For images of the base of a weight, it is useful to try regular flash and non-flash shots but also to take the image using an open window as a background and with no flash. That way, subtle features of the base finish can be highlighted - but the weight needs to be moved around to find the best view.