If you're going to do any kind of digital artwork, be it redoing the line art from a scanned image or just drawing from photoshop intirely, there's two very important tools anyone should know about: the Brushes and the Pencil tool.

Pencil Tool: Some Artists prefer the Pencil tool. It's cleaner and easier to correct mistakes. Unfortunately it looks very blocky/pixely, and I personally don't like it because of this. For redoing line art it's probably fine, but if you're wanting to do digital art only, it's probably better to go with the brush tool.

Brush Tool: Mine and many other artists preferred method. It has a soft blur around it's edges, and when you have a tablet this can simulate pencil drawn artwork better than what the pencil tool can do. Contrary to popular belief (and purist who seem to think digital art will one day kill "true" pencil/paper works) you can NOT replicate natural pencil work this way. Not very easily anyway.

These two are pretty much all you need to know about when starting out. Play around with them and see which one feels better and good luck!

other notes:
for those curious enough, how about we learn what the difference between scanned work and digital artwork? Check the next page to find out!