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:
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.
Step 2: Plan & Prep
Lay the contact paper on a large flat surface (a floor is good) and tape it down. If it's a large design, you can fold the paper into equal sections to create grid lines before you tape it down. (Don't forget to unfold it!)
Make sure the paper is right side up/clear side up! Place newspaper or other protection under the contact paper if your design extends all the way to the edges- you will be painting on this sheet and you don't want to paint the floor.
Repeat this step for each part of the design.
Step 3: Sketch, Paint & Cut
Once you're happy with your design, paint it. The paper is transparent so it takes at least 2 coats of paint to cover the design evenly.
Let the sheet of contact dry for at least an hour before you handle it. If it's a humid day, you will need to put a fan on the sheet to speed things up. You want to make sure the paint is completely dry so you won't get any on the wall.
Don't throw away or ruin the scrap pieces of contact paper! You can use them to add stuff to your design or you can use them for another design.
Step 4: Layout & Apply
Use your design idea sheet to guide you in the placement of each piece or if you want to get specific, measure and mark where the pieces should go.
When applying your design, start at the center or main focal point of the design and work out from there. This keeps everything balanced and straight.
As you place each piece, smooth it out with your hand to make sure there are no air bubbles or pieces that are sticking up.
Every few pieces, stand back and check the design for proper position. Reposition the pieces as needed.
Step 5: Changing colors
1. Paint over it. You will need to paint really close to the edge. (You may get paint on the wall)
2. Remove each piece, paint it, and reapply it individually. (You won't get paint on the wall but it will take longer)
3. Start over in a new color.
In my case, the black against the green wall was too harsh for my taste, so I softened it with some brown paint. I also added white and blue elements by painting scrap pieces of contact paper, cutting the elements out, and applying them to the design.