Draw a long rectangle for the bus body
Add a slightly curved roof line
Sketch a smaller rectangle or rounded shape for the front windshield
Add side windows as a row of rectangles
Draw the front and rear doors
Add two large circles for the wheels
Draw smaller circles inside the wheels for the hubs
Add the front bumper
Add the rear bumper
Sketch headlights at the front
Add taillights at the back
Draw mirrors on the sides
Add a destination sign or route display at the top front
Include details like handles, lines, and panel seams
Erase extra lines and clean up the outline
Color the bus as desired