Start with the real relationship
The best birthday notes do not need to be long. They need to feel specific. Before writing, name the relationship in plain language: old friend, newer friend, partner, sibling, colleague, neighbour, or someone you admire from a distance.
Use a simple three-part shape
Try one memory, one quality you appreciate, and one wish for the year ahead. That gives the message a beginning, middle, and close without making it sound formal.
Keep the tone honest
If your normal voice is playful, write playfully. If the relationship is tender or complicated, keep it gentle. Avoid claims that feel bigger than the relationship can carry.