Interesting information from the website: Art gallery .... :
General recommendations:
1.Semku should be carried out with a tripod. You can use any photo or video tripod.
2.When a tripod must use the "timer". For those who do not know: "Self-timer" - is a camera mode when the camera photographs at once, but after a few seconds after you press the shutter button. So Prevent disabling shots from shaking your hands and thus blurring the pictures.
3.Pered how to shoot, opt out of date and time at the camera. Strangely enough, but such mistakes occur quite often.
4.Fotoapparat must be exactly in the center of the picture and always strictly perpendicular to the surface of the painting. Otherwise, the picture becomes a trapezoid.
Read more (most useful):
http://www.arthit.ru/useful/to-make-photo-r.html