I forgot to mention that the program I am using is MangaStudio which has a number of free brushes you can use. For the line work I used mainly the G pen, but used the brush for the eyes and eyebrows.
Anyhow, for line work you don't need to work into the small details: just get the main lines done and focus on that in the finishing stage. A tip I always toss out is to use a separate layer for the background and main figure so you don't have to redraw the whole thing.
Please make sure that your line work is nice and smooth so colouring is much easier. If you want it to have a sketchy look, it would be best to do that after the colours and shading is done.