Using fine liner, watercolor pen and or paint really puts you out of the comfort zone, especially compared to using tools such as pencil, charcoal, pastel or even oil paint. Why? the damage of the first group is non - erasable, we have to actively mitigate the collateral damage, the other group is not ''perfectly erasable'' as well - because all will have some smears depending on how you applied it and what things you used. Non erasable tools shine in helping you be more intuitive of solving drawing problems, ratio judgment of sizes and placement, stroke confidence such as hair and eye flow and many more.
In this case I draw Kosmos from Xenosaga in 45 minutes: Try drawing something similair like this, only if your a beginner I suggest starting with small drawings. This way you will improve your sketching and leverage these ideas, tips and secrets into your advantage. Video on this topic below.