Well, you may know nothing about cameras, but you need to learn if you want to use them properly.
Presuming you have a digital camera. or film camera
1. Make sure you have the correct "white balance." Sunlight, flouresent and incandescent light are all different temperatures measured in degrees Kelvin. I don't remember the tech stuff, but sunlight is bluer, incandescent more yellow and flourescent greener. Our minds compensate for most of these differnces automatically, unless you're going from one to the other quickly. Your flash is set to the same temperature as sunlight. Find the button or program that says White Balance and press it til your image looks right with white whites. Using film, you'll need to get the proper filter or indoor film to compensate for the lighting.
2. You should have a "Macro" setting, usually indicated by a little flower icon. This allows the camera to get up close and personal. Lacking this, use your zoom and step back from the subject and zoom in. With an SLR, you'll need a lens with a macro feature, extension tubes, or a magnifying adapter. In either case, if you have a real simple point and shoot, you're out of luck.
3. This applies the same to both types of camera. Spot metering is essential for small subjects. Find the button or program that sets this. You should have some sort of target, a cross hair or circle in the middle of the viewfinder. This tells the camera you want it to adjust to this spot. The shutter release may have a detent position where it locks the focus and meter to the center of the image and will alllow you to adjust the position without resetting the aperture and/or shutter speed.
4. Lighting, this, too, applies to both and follows from #1. If you need to use your flash, you need to use the zoom feature as mentioned above. Flash and macro don't mix except in some very sophisticated equipment. Use two or three adjustable light sources, flexible desk spots, as in my "studio" below. Adjust these to eliminate unwanted shadows and to highlight what you want. Most of these were taken in this setting and all were taken with a Sony FD95 2.1 megapixel digital camera.
5. A tripod will be necessary for much opf this unless you have a very good, fast lens. That's one of the strengths of my antique, really good glass. Most of those pictures were taken hand held, mostlly because a tripod wouldn't fit in my workspace and when I'm doing real close ups, the lens is within an inch of the subject.