Nail the ending. People forgive a slow start but they remember how you left them.

What people carry away is disproportionately the last part, because an ending is what the whole thing gets filed under in memory. A weak opening costs you some patience and can be recovered from. A weak ending rewrites everything before it, since it is the note still sounding when attention returns to ordinary life.

Give the final section a pass of its own, separate from everything else. Ask what you want someone holding as they walk away, and build backwards from that.