Graphic Design Project

In our Humanities class, we are trying to figure out how to take pictures we've drawn into Photoshop. Right now I'm having trouble with this because my pictures are overdrawn, because that is how I draw. I'm not able to use the Magic Line tool and so I can't work with the details of my drawings. Once I am able to get these into Photoshop, I then have to paint them which I think will be equally hard. I need some tips on how to work with Photoshop so I can use my original drawings. Do you have any ideas?

I found this one site called Photoshop Help, but it didn't seem to address my issues: http://www.photoshop-help.com/ except for the following information:

"Photoshop Painting and Editing Techniques
Press shift while dragging with any paint or edit tool to draw a straight line..
Always note the opacity in the Option palette while painting to avert mistakes
Press a number key to change the setting of the Opacity, Pressure or Exposure slider bar in 10 percent increments
Consider making a new blank layer and paint there. Paint separate pieces or objects. This will allow you to make opacity adjustment in the Layers palette. It's also easier to erase unwanted areas.
If you're retouching with the Clone or Healing Brush tools, it's essential to zoom in very close to the area you're working on and use a small soft brush.
Always note what your foreground and background colors are. Check the tool box near the bottom for the two large squares. Click inside one of them to access the Color Picker. Play with it awhile and get familiar how the colors can change.
In the toolbar click the curved double arrow to switch the background to foreground. Type the letter X and that will switch the colors too.
If you want the color to be black and white then type the letter D and you got it.
Go to Window> Swatches and the Swatch palette will come up. Click on a square and that color will be your new foreground color.
Go to Window>Color and the Color palette will come up. Click around on the colors and drag the sliders a bit and you'll see that the foreground color in the toolbar changes with you. Have fun, you can't break Photoshop. "

I'm interested in learning how to use Photoshop better because I believe that art can convey things about history. Just think of all the paintings of Presidents or great battles. I can imagine a painting about the atomic bomb that would show a mushroom cloud and the grass as the city. Paintings can be used to teach people things about history so that perhaps in the future millions of people might not be killed by war.