Use the principles of perspective drawing to create a 3D template for your design. Examine the background imagery you want to use for your mural to determine the number of vanishing points you will need to bring your design to life. Determine the location of the vanishing points by placing tracing paper over the design and tracing all of the horizontal lines in the design with a ruler. Identify the points where the lines would converge if they extended to the horizon and label them as the vanishing points. Repeat this process to determine the vanishing points for vertical lines.
Use the vanishing point or points as markers for placing additional horizontal and vertical lines when you add elements to the foreground of your design. For instance, if you are placing a car on a street in a position where the car appears to be driving toward you, make all of the car's horizontal and vertical lines extend such that they would converge at the vanishing points if they were to extend indefinitely. Experiment with adding elements to your design by drawing them in this way on separate sheets of tracing paper on top of your background.
Create a final design when you are satisfied that your image looks sufficiently 3D. Stack your best tracing paper ideas to put them into position to use as a template for your final design. Transfer your final design to transparency paper with a marker.
Place the transparency paper containing the design on an overhead projector. Turn on the projector. Adjust the size and placement of your design on the wall by moving the projector forward and backward.
Trace the 3D image onto the wall with the pencil. Paint the design on the wall with latex and acrylic paints. Paint the background sections first, starting at the upper left-hand corner and working to the right and down to avoid smearing the paint. Allow the background to dry before painting over it to add details. Add shading for additional 3D effects by determining the location of the light sources in the design. Create shadows with black paint on the far side of objects in relationship to the light source. Highlight objects facing the light source with white paint.