...is not impossible,
at first getting nice line art in photoshop is kinda hard and takes lots of time,
specially since the setting on the burshes ain't the best...
so i decide to give some tips on good Line Art I know I'm not the best but anyways
oh make sure to click on the image for a bigger view :l
Step One: give out a good draft of what you wanna draw,
personally this is a old drawing but I liked it, you don't have to start from pencil, it can be just out of the canvas,
Step Two: make sure you setting on the bursh is a hard size 3 bursh, :L
Step Three: open up a new layer and star to trace over it, make sure each stroke is fast, so it has less mess, don't be scared to rub out any big errors
lol after the image is complete the lines would look really thick...
Step Four: start rubbing off some bit that you think make the image look too thick, so it looks like something like this;
other results :
then use a size three brush to rub off some bits, that you feel is too thick but not too much, so it should look like this after