Photography, strange as it may seem a rather complicated process. Get a camera and "poke" button will be able to each. This photographer has to take care of the light, mood models, background and more about a whole heap of other small details. Let's talk about the light. Shoot the best, of course, when the light is scattered. It's either the morning or evening hours 17.00-20.00. At this time the light quite bright, so you can easily drop that shots without the flash, which makes them just flat. Natural light will emphasize the details and contours.
I try to use the flash only when it can not do without. Sometimes I like to shoot at high iso, than with flash. If you take an umbrella or a scattering shoot in the studio, then use the flash is justified. But I still prefer to take pictures without using it, frames are more vivid and brighter. Shoot against the light, unless you want to get a silhouette! Sometimes shooting against the light, can give unexpected results, very interesting picture. But, more often if it was not specifically provided, it is not very good. Background. Imagine this scenario: you shoot very beautiful girl, but on the background of someone you writhe smiley face, or model in a black dress and you take it off to a dark green background.
Be sure that the clothes get lost in the photo. Always use a background lighter or much darker, so that separate subject. Very nice background is obtained by using small aperture.