Photoshop: Learning

This is one of my first attempts of developing my own illustrations using photoshop. I learned how to adjust the levels and how to multiply and create new layers to use brush tool to add colour. I like the effect of the colour that shows outside the line however I would like to learn how to use colour so that it fits neatly inside the image. I have tried looking at tutorial online but I am finding them had to understand. I also took the advice that was given in my tutorial to ask other people in the class for help but I find it difficult as many of the people I ask don't know or aren't in college very often doing their work at home.