I actually do pretty well building a range of tones slowly through hatching and cross-hatching. Kinda like what the old master engravers like Durer did: [link] Of course in that image you can see that for some surface textures he used shorter hatch-marks. But he uses straight hatching as well. Working larger makes it a bit easier.
Stippling and washes, as already mentioned, are another way to go. You can also consider working in a more graphic style, breaking down the midtones into lighter and darker areas. Personally, I get more "pop" in ink pieces by dropping out the lighter midtones and simplifying the overall range somewhat.
With greyscale you have a lot of value to make something smooth in. With pure ink you can try stippling or washes. Small hashes can work but it every approach depends on context and what you're going for.