Assuming you're using Maya, all you have to do to texture something is right-click an object, choose Materials>Assign New Material>and then select a specific texture. (or whatever they call that list of items) Most people start off with blinn when learning. After that, a window will pop up. This is the attributes window if I remember correctly. In here, you can choose a colour for the object as well as a host of other things. To the right of the colour slider, there is a box. If you click it, another window appears with several textures avaliable in Maya. One of the selection is "file." This option lets you browse the files in your computer for an image which you can use as a texture. Obviously, you can scan items for an image, search the internet (google is good), or take pictures using a digital camera.

Light can also improve how your piece of work looks. I've also heard a lot about ray-tracing, although I haven't the foggiest as to what it is. Possibly something used in lighting.

Well, hope that helps you out a bit, mate.