Draw a wavy horizontal line for the wire.
Add small evenly spaced bulb shapes hanging from the wire.
Make each bulb a rounded teardrop or oval shape.
Draw a small socket at the top of each bulb.
Add a tiny cap and short connector line above each bulb.
Repeat the bulb shapes along the wire.
Vary the bulb sizes slightly for a natural look.
Add a small highlight on each bulb.
Draw simple filament lines inside each bulb if desired.
Outline the bulbs and wire with clean, smooth lines.
Erase any extra sketch marks.
Color the wire dark green or black.
Color the bulbs in bright festive colors.
Add a soft glow around the bulbs if desired.