Thought I'd start a thread since this is a regular issue, and no doubt others will have more (better) professional tips.
Cell phones now have a 2048X1152 (2.4 MP) setting which is adequate for images to be posted on forums. For enhancing and cropping the image on the photo hosting site, it is important to minimize unneeded background in the original image ie. fill the view finder just with what you want to capture.
Plenty of sun here in the desert, so I set up outside with the object in the shade of my neighbor's house, with the morning sun almost clearing their roof and shining on my stucco. Even in the winter (here) direct sun gives too much glare, but the sun behind thin clouds works OK.
I use a dark grey
solid background 10-12 inches
behind the object which gives the image a 'floating in space' look
This took a bunch of tries to get the lens to focus on the defects in the bore. The sun was shining on the wall behind the barrel, which was sitting on the dark grey mat
