What I can see is that you have a good eye for photography. You are playing with light, and that is what photography is all about.
Photo: Christian Krenn
This is definitely not a bad first try.
Exposure and colour are fine. The subject is very well defined against the background.
Composition: To me, this is a play with light and shape. I think that diagonal approach is nice. Your central point of interest is very centred, and I think the picture would profit from a heavy crop in the bottom. Cut away 3/4 of the space under the screw.
I have this possession
about distracting elements. It could be the element in it self (nothing to do with the subject) or the shape, the colour, the exposure or the focus of an element. All of this will either support the main object, OR distract.
In this picture, the out of focus foreground is distracting. Even with the cut I suggested, it is still distracting. The wood on the left is also very dominant, but as it has the same colour and shape and orientation as the main object, it works to have it there. I think it supports the main subject. However, in this photo it cannot be sharper than the main subject (or part of it).
Seems like the DOF (depth of field) is misplaced. The focus area (?) does not cover the entire screw (which it should). Personally, I think all of the wood on the right should have been sharp. This should be easy accomplished by stepping down the aperture. Put the camera on a tripod (or any other support). Essential for this kind of photos.
This is a kind of photo that could be sold.
Would you give it another try? See if you can maintain the exposure and colours, but fix the focus. And try to get the screw more off centre.
Also, just a hunch, try to unscrew the screw a cm or so, and see what happens.
Photo: Christian Krenn
Exciting picture. I think the composition is pretty good. Again a picture that could sell, if it was technically perfect.
I love the colour tone and the shadows. If you used AF here, it seems like it is back focusing a little. But here that works better to have a foreground out of focus. I would prefer to move the DOF area a little to the front. Just a little. (See a comment about how to move focus at the end)
Exposure: That "thing" in the middle is too dark for my taste. The colour get a little dirty because of the underexposure. Obviously, if you were to expose after this object, the nice shadows and the golden colour would disappear. We have to find a way light it up. How much will be a personal preference. Set up your camera on a tripod, place the object, set the light, compose the shot, and use the same exposure as you used before. Now, use a Maglight, and some linen or fabric. The small light source will give a very hard light (the smaller a light source is, compared to the object, the harder (and more unpleasant) the light is. That is why pro's use diffusers (bouncers) on their flash(es)), therefore try to diffuse it with some fabric. Experiment with direction. We do not want this light to light up the shades, so you might also need something to shield this. See why a tripod is great?
You should probably just give it so much more light that the object is more defined. Another way of lightning up is to use some sort of reflective material, but it might be harder to control here.
Does it make sense? Hope you will try again.
How do you move the DOF closer?
It is the same as moving the focus point closer.
I presume you have the camera on a tripod, and it is a setup where nothing runs away.
You can either switch to MF and then adjust focus just a little closer or focus on another object that is just so much closer as the distance you want to move the DOF, and then lock AF by half-pressing the shutter. I prefer to introduce a object myself, a tiny bit of paper, with some black lines in various directions, so the AF can pick it up. Then lock the AF (or switch to MF), remove the paper, and take the picture.
You can also tilt/swing the camera to find a suitable object, but there are a few points to this.
First, after you have fixed the perfect composition, you may not want to move the camera away from this.
Secondly, the focus plane is not flat, so unless you know how it behaves with different lenses, it might not give what you want.
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Kind regards
Øyvind Strøm
http://www.norwegianviking.smugmug.com
http://www.pbase.com/norwegianviking 
