Adobe PhotoShop ™ is a more advanced art program then what normally comes with your computer. You can buy this program anywhere that sells computer software. Adobe PhotoShop 6.0 is similar to Adobe PhotoShop 7.0 or any other so try it out.
Step 1

Open up a new document of course, so you click "FILE", "NEW" and you set the dimensions.
Step 2

Set it, here you see 500x500, but you choose whatever you would like.
Step 3

Make a layer. Once you have your canvas size the way you want, you create a new layer. First, you have to click "layer" "new" "layer." And name your layer. Name it "white"
Step 4

Fill in the new layer with the color white.
Step 5

Create a new layer. Now you will start to sketch out what you would like to draw. Click on the colors and pick one.
Step 6

Pick a brush and apply the settings.
Step 7

Draw. You don't have to worry about neatness, just draw away! Here's a sketch.
Step 8

Outline it. Now that you have your sketch you need to outline it to make it neater. Create a new layer. Click the pen tool, and click "freeform pen tool"
Step 9

Outline one of your lines. Since the pen tool smooths your line, you may need to erase and redraw it. (not the whole thing only the line, don't worry)
Step 10

You have a line. Now you need to stroke it. Right click and click this and then.
Step 11

Set to paintbrush.
Step 12

You should have this now.
Step 13

Delete the rough sketch. Delete the old line by doing this. Right click and select delete path.
Step 14

Repeat for all the rest of the drawing. Here we see this:
Step 15

Clean up. You don't want the yucky blue lines right? You do this:
Step 16

You have this.
Step 17

Look at the lines. Some are thick and misshapen what we need to do is taper.
Step 18

Grab the eraser and taper the lines by erasing the edges of the line.
Step 19

Do it to the rest of the lines.
Step 20

Add color. Now it is time to add color.
Step 21

Go to the colors and pick one that you would like. Create a new layer Okay, now you color it!
Step 22

Do the same as you did with the blue and.
Step 23
Step 24

Continue to add more color.
Step 25

Use the magic wand. Now the lines are all out of the image right? That can be easily fixed. Click the "magic wand tool"
Step 26

Click on the line art layer and use the wand and click the canvas. This should happen:
Step 27

Go down to the color layer and hit "delete on your keyboard, extra coloring is gone
Step 28

Click ctrl+D. Okay. So repeat until all your coloring is finished.
Step 29

Shade and highlight Create a new layer Click the airbrush and set to 10% opacity at the top, and pick a color darker then your original. Wherever you think there is shade go over with your airbrush.
Step 30

Keep going with the body.
Step 31
Now pick a color lighter the your original color and where you think there's light, highlight it! Add details like the eyes.
Step 32

The final result
Tips
- Practice, that's the only way to get good at it.