The brush/brushes I use is first of a large soft round one from Daler/Rowney that gives the initial even soft spread (not precise). Then for the details and the way I get it more precise is with a smaller nr 4 square stiffer brush which makes it posible to apply more pressure and therefor more darkness+precision. How I block out larger areas even, I start out for example with the overlay block on the left, filling it out with the large brush and I even go over the lines to get i even to the edge. Then I take my kneaded eraser and erase precisly to the edge of the block. Then i take the smaller brush and continue to darken it in within the limits of the edge. From there on you have to use pencils if you want it even darker.
Another thing is if you use the graphite powder from derwent then it is almost impossible to get it even and with out spots. It is really a bad brand for that. When i tryed it, it just became dark so fast and it maked spots etc. But the powder I got a hold of from Sennelier, it never makes spots and is so easy to spread out evenly, you can continuously mold it while you have the extra powder laying on the paper. Last things is that when you do graphite powder then you should be really careful not to touch the paper and leave fingerprints, it really shows up clearly and it ruins the even surface. "
Niklas Andersen website: LINK