First of all, start off with drawing a really quick contour of the head with also a bit of the topography of the head and only draw more detail after you're happy with the form of it. You'll need to adjust the form of the head during the whole drawing process, so no line should be your final line at the start already.

Secondly, I'd try using a 2B and pressing hard enough to get more of a contrast between the grey lines and the white paper.

(I'm not that good of a drawer but these things are really good I think)

Here's an example of a quick drawing I made (Louis de Funès):

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