There are a couple of things I would try, I did and it really helped me....

1 - Find a good basic photography book, not one of those that tell you about how to transfer files from your CF card to the PC, but one on photography itself, go to your local book store and search one out, it doesn't matter how much you already know about photography if this is you first DSLR It's worth learning again.

2 - Use eBay to find a cheap prime lens, I'm a Canon person so I don't know the Nikon range (Edit see here), but I got a 50mm F1.8 for about £50 and it has really shown me what I can do with my DSLR. Zoom lenses are great, but a prime lens will force you to think about your shots and naturally improve. I have found that although this lens isn't the best quality best built thing out there it has been the most rewarding to use, of course the point of an SLR is to have a collection of lenses so I found this way a great way to make a start.



A recent shot I took from my table at a recent wedding with my 50mm F1.8, lighting conditions were very poor and I was sat across the room, flash was bounced off the ceiling, and knowing the bride I feel I captured "the moment" here.

Cheers

Cris.