auzzieboomerang
Do you have photoshop? Using the pen tool has always been the best method for me to do it. Although if you have a tablet that helps too.
It's possible that they mean traditionally. Not everyone has moved to digital drawing/inking.
anyway, my suggestion would be to get a new piece of paper, and a lightbox (Whether ir be a real light box, something that you fashoined out of glass, a cardboard box and a light, or using a window).
Take your sketch, then place the new piece over it. Using a light source, you should be able to see the lines. If you are having a hard time, use tracing paper instead of regular paper for this.
TRace it.
Yes. Trace. I realize this is not third grade.
Point is, using a pencil, trace where you want your lines to be, and try to avoid being really sketchy.
After you finish that, you should be able to ink that without a problem.
---
This is of course if you mean traditionally. If you mean Digitally, I can't help you there XD