Using the chalkboard or an easel to show a brief lesson outline can help you cover material efficiently and effectively. You'll find that writing verses on the board will help students follow and anticipate the direction of your lesson, resulting in better discussion. It will also help you stay on task and more easily cover material, fast.
EXAMPLE: When teaching the second coming from Isaiah 26, I had written on the easel:
v 1 - What will happen
v 2 - Who
v 5 - Why
vv 6, 11 - How will earth/men feel
vv 13-15 - But the righteous... (see footnote)
vv 16-18 - Isaiah is still sad (What does this tell us about Isaiah's personality)
vv 19-22 - "visited" (more prophecies)
v 23 - Jesus comes in glory, cf 23a