Choose a lightweight material such as plywood, balsa wood, or thick cardboard
Draw a boomerang shape with two or three angled arms
Cut out the shape carefully
Sand or smooth all edges
Round the leading edges slightly and keep the trailing edges thinner
Make all arms equal in length and angle
Add a slight twist to each arm if needed
Paint or seal the surface if desired
Test the boomerang in an open outdoor area
Adjust the angles and weight if it does not return properly