Being a newbie, I would like to have some comments on my current skill level and quality of my current equipment. I own a Nikon D7000 with 18-105. I am not very much satisfied with the quality of photos in terms of details and sharpness. Maybe you can have a look at the linked photos and see if this is the best I can achieve with my equipment.
I have a few general comments that might help to either explain what you are seeing or improve this test for the next run:
You are really trying to achieve macro like images it seems, and the Nikon 18-105mm VR is not a macro lens. The closest you can get is about 18inches and the maximum magnification ratio of 1:5. For macro you want 1:1.
The images on Flickr are only approx 1024px at the widest, where as the D7000 is capable of producing up to 4928px wide images. Since we are only really seeing 1/4 of the image or so(or at least of its capabilities) it is hard to say how sharp they are.
Are you shooting hand held or on a tripod? For macro like this(or attempts at it) I would suggest a tripod if you are concerned with sharpness
The shutter speeds chosen aren't all that fast(1/200s eg), it seems like both shots were taken on fairly overcast or cloudy days. If you are testing for sharpness, make sure you have sufficiently fast shutter speeds which can be obtained by using a tripod.
It is normal with digital photography to expect to do a bit of sharpening in post processing, if you have done none and the camera is not set to add any to the JPEG, you really would want to add some in to get what appears to be a good sharp photo at these resolutions.
If the Nikon D7000 has any type of micro adjustment that allows you to better adjust a lens to suit a body, I would look into doing that and performing those adjustments. That can greatly improve any small issues with focus and sharpness of a photo as you expect.
Further - I'm not sure what you aren't satisfied with "in terms of details". I think you have to be more specific with this, where you see the issue, etc. On the surface I don't see any issues, the images both look fine to me, but to get a better idea I would try to take into consideration the above notes I have and re-shoot a few test shots. If you really want to do it the right way, I would take a look at some of the other topics here explaining how to properly test a lens:
Both appear pretty sharp to me right at the spot that is in-focus. You just have pretty wide apertures thus pretty narrow Depth of Field, so most of the image isn't in focus. (The second image claims f/8 in the caption, but shows f/5.6 in the EXIF data.)
Also, I believe with that lens, f/5.6 is wide open at the 105 end, and lenses typically aren't their sharpest at that spot. Try shooting at f/8 and see how the results compare.