With this method you can add any painted design to your wall and remove it if necessary.
This is a great way of decorating an apartment or other space where painting is not allowed. This is also a great way of decorating a baby/kid's bedroom since you can create everything from cartoon characters to pretty landscapes on the wall.
* This project is not for the impatient or the easily annoyed. You will be painting, handling small pieces of sticky paper, and probably dangling on chairs or ladders to apply the design, and it will take a bit of time to get it done.
** Keep in mind that contact paper may peel the wall when removed. Avoid super sticky contact paper for this project. The brand I used for this project didn't affect my wall.
EDIT: I just saw a very similar project here on instructables called DIY Vinyl Wall Art (http://www.instructables.com/id/DIY-Vinyl-Wall-Art/?ALLSTEPS). I came up with this idea on my own but I think I should mention the other instructable in order to comply with the BY-NC-SA licensing terms since the two projects are so similar.
Step 1: Supplies:
1. Transparent contact paper that isn't super sticky. I used the Clear Transparent Con-Tact brand ($4 at Walmart). You can also use white contact paper for this project. I use transparent because I feel it looks better since it's thinner than white or pattern paper.
2. Acrylic paints. I don't recommend using watercolors.
3. Pencil, scissors, tape, and paintbrushes.
4. Design idea printed or drawn on a sheet of paper.