Isolate the object of interest
Draw a simple outline or dot for the object
Identify all external forces acting on the object
Draw each force as an arrow starting on the object
Label each force clearly
Show the direction of each force
Make arrow lengths proportional to force magnitude if possible
Include weight acting downward
Include normal force if the object is on a surface
Include tension if the object is attached to a rope or cable
Include friction if there is contact and resistance to motion
Include applied forces from pushes or pulls
Include spring forces if a spring is present
Choose coordinate axes if needed
Resolve angled forces into components if necessary
Check that only external forces are included
Verify the diagram matches the physical situation