The other answers have said it all. However, I am adding my 1 cent. As a fellow (software geek) I'll try to add something from a geek perspective.
As far as my study on D5100, it's one of few best camera in this price. It's enough for even mid-tier professionals, let alone for beginners.
Besides all the learning tips in other answers, I will add that you should read the camera manual thoroughly. Without that you may never be able to utilize your purchase to its full potential. You should master your gadget like your own body. To punch a bad guy, do you have to think and plan how and what hand you should use? Master your device just like that.
I wonder how many people spend thousands of dollars on gear for which they don't even have the patience to read the FREE manual. How they even passionate enough to take great shot ?
Now, push through the basics and deep understanding of composition, color, and lighting. Hello, I am NOT talking about lighting gear.
And practice (at least try) just after learning something new. Practice with a same subject in hundred combinations of composition, angle, lighting, exposure, white-balance, etc. From each shot, you will be learning.
Beware, you will also in need reading a lot even to be a decent photographer.
I am amazed that nobody mentioned about a reliable monitor. To edit or understand your properly, you will need a wide monitor (at least 20") that re-produce true colors. If you edit/review your photo in a low-quality monitor, your effort is definitely gonna be messed up.
Bon voyage ...