My favorite tool is the yellow number 2 pencil. I have tried a lot of the different various drawing pencils out there and I do use them for different things but I use a yellow pencil for my graphite work 90% of the time. I like the way the line flows from the point. I try to keep at least three sharpened all the time that I am working. A lot is going on when I use them and I don't want to be interrupted by continually sharpening. I just switch off when the point gets too dull for the section that I am working. One of the things that I have learned is a sharp point is crucial in order to gain the type of detail I want. I suppose a lot of that comes from my experience as a jeweler and repousse artist. I still tend to work small and an 8 x 10 seems huge right now.
The quality of line, let me say something about that. Pressure is everything. A light pressure gives me a light grey. More pressure darkens up the line as I bear down. Ok, maybe that seems to self evident but think of it this way: I get at least 3 to 4 levels of grey in the same stroke depending on the pressure. A lot can be done with just that. Sharpness counts too. A fine point can only take so much pressure before it snaps. The only way to learn that is to break a few points. A blunter point can take a lot more pressure. That is one good reason to use several pencils at the same time because I can pick up one that is slightly used and apply a dark heavy wide line when I need it.
Other tools? I use several kinds of blending stumps. They vary in hardness and size. I use several different erasers also. Kneaded erasers are good for feathering, i.e. removing just some of the graphite to lighten areas without taking all of it up. Sometimes I trim shapes out of my white eraser to get a knife edge for branches or narrow parts. I even use a powered eraser on occassion.