Well, firstly, I think the big question is just how much programming experience you have. Some examples of your previous works may be handy. Basically, first you need to be sure that you're able to take on something like games that would work on actual consoles- they generally would require much more work.
As for the rest of your questions, in order-
As for programming languages to work in, if you want to get on consoles the only way I know of that would be accessible to someone on what I'm assuming is a pretty limited budget would be XNA. XNA isn't itself an actual language but rather an add-on (or something like it) for C# that allows you to make games that will be compatible with Xbox 360. I don't know much myself about it but maybe some others could add some info in or direct you somewhere that's better.
As for graphics, there are a couple of things to know.
One is the concept of textures. These are generally just 2D images that you could either have on their own or on a 3D model, which gives it its actual look rather than just a bunch of grey blocks.
I am no graphics master but in most cases basic 2D images can be loaded with pre-made functions that can load in the images properly. Although, I'm fairly sure for that you would need an add-on library for C# for that, but that hopefully wouldn't be too hard to find. Keep in mind though that my only C-style experience is with C++, and even then it's limited so I may be wrong in some way.
Then there's the actual 3D drawing, and I'm assuming you would want 3D if you want to make games for consoles.
Again, to do 3D drawing you will need an add-on that lets you do 3D functions, but again, this should not be too hard to find. These would allow you to do some basic drawing in 3D (basically all you'd need to get a basic 3D landscape set up).
Then there's the concept of models. To me models kind of come into their own category from basic 3D drawing because if you were to draw an entire model (say a person) through direct code it would be very long and hard to write. So basically a model is a 3D object that you can create in all sorts of 3D modelling programs, for example Blender. Code-wise, all it is is a file that contains the data for the model that, when read into the program and used correctly, can be used to draw that model with you drawing each bit yourself (although you would have to write the code to actually draw it using the data). This would require to first know how to read the file properly, and then draw it all, which is why I'd consider it more difficult than "basic" 3D drawing.
Anyway, I think that's your general questions answered. Anyone else (u9, I'm thinking you :P), feel free to correct me where I'm wrong 'cause I don't know entirely what I'm on about with all this, but I'm hoping I got the general gist of it right.
But yeah, hope that's of some help.