here is some info that will help with getting settings right, keep in mind good light and shutter speed all work hand in hand
http://www.sederquist.com/claexpos.htmlf-stops (Depth of Field)
Your other creative camera control is the aperture (opening) on your lens. We measure the size of the opening using f-stops. Each f-stop is twice as large or half as small as the one next to it. Thus, when you set your lens at f/8, and then adjust the lens to f/11, you're letting in half as much light. Conversely, if you set your lens at f/8 and then adjust it to f/5.6, you're letting in twice as much light. On a 35mm camera, you'll find f-stop settings like f/1 (wide open), f/1.4, f/2.8, f/3.5, f/4.0, f/5.6, f/8, f/11, f/16, f/22, f/32. To gain a bit of light, you'll also see non-standard apertures such as f/1.8. f/3.5 or f/4.5.
Why bother with all this? As you go higher in f-stop numbers, you increase the front-to-back distance (depth of field) in your photograph. Thus, if you take a picture at f/22 (a very small opening), you'll have most of your picture in focus. A way to remember this is as you go higher in f-numbers, more of the picture is in focus.
Another factor to keep in mind is that your depth of field decreases as your camera/subject distance decreases. Thus depth-of-field becomes a major challenge in close-up photography. Depth of field also decreases when you use medium or large format equipment, such as equpment that uses 120/220 or 4"x5" film. Depth of field decreases, too, when you use telephoto lenses.
