With Nikon D5000, how can I make the pictures I take more sharp?

Many pictures I take look soft like this one:
Sometimes even under sunlight subjects look like that, although normally the strong light of the sun makes them sharp.
So, is there a camera setting I can use, or should I use Photoshop?
Thanks!

Added (1). OK, I don't remember what settings I used, but this is the JPG

Since you posted a png file and not a JPEG, it is impossible to see what settings you used.
Usually the sharpest images are produced with the lenses set two stops down from the widest aperture.
Photoshop can only make things appear sharper by using the unsharp mask.

You could try reading the manual or learn to use the camera properly…

The lenses has the best sharp in f8 f11, i think the problem is that the focus is not in the eyes so you think is not sharp, but obviously is the kit lense!

The problem is not in the lens or the camera, but in the lighting, obviously shot in the shade which gives this 'flat' without contrast lighting. There's a big difference between diffused light and being in shadow. There's some evidence of a little camera shake, slight amounts of which will take the edge off the sharpness, but the main culprit is the lighting.
What lens did you use? Wide range zooms have so many compromises not least of which is low contrast, this would make things worse even in decent light especially when used at their widest aperture. The difference that a good prime lens would make to shots like this, even wide open, would be enormous.
Chris

Forlorn Hope, isn't this what the person is trying to do? How about you be helpful and give some advice or don't post.