Point of view (POV) is one of the most important aspects of setting up every shot. You need to start with that and you can build all other aspects up from there. Choose your POV (sometimes called perspective) and then worry about shutter, aperture, lighting etc.
In this shot, the subject was sitting at a table and I jumped up on a chair with flash in hand, close to the ceiling and bounced. I obviously used a very small DOF - I think 1.8. It was a one shot deal. I was never going to recreate that natural expression; which of course was her not being amused. If that shot didn't work, I would have hopped off the chair and taken a different approach. As luck would have it, it worked! The only post editing I did was slight color correction and cropped it smaller.
This shot is only as interesting as it is because of the POV. Try your shots by looking up at people, down at people. Shot them head on. Try a profile. It will add interest and often times drama to your portraits (and other shots of course). The more you practice, the happier you will be with your results.
"Professional" POV Tips: These are only jumping off points.
1. For adults, try shooting just slightly above your subject's eye level looking down. It is typically a flattering angle.
2. For shorter subjects (shorter than you) try getting down lower, perhaps looking slightly up at them. You don't want your shots to be tops of heads.
3. For kids, get LOWER. Shooting at their level or looking up at them will dramatically improve your child shots. Look at the shot below. This child is at my level and it is a very pleasing point of view. I got down on one knee. The person taking a picture behind me (a family member of all people) stood. Yes, stood and looked down. Without showing their results, just guess which one came out better.
The next time you can use a child as a model, try capturing a few shots looking up at them. Have them stand on a rock or jungle gym and put the sky behind them on a crisp Fall day. If done well the results can look very amazing. And why? We aren't used to seeing children at that angle. And that creates the interest and the drama.