Propose at the place where you first met.

If you're both musicians, play a song together.

If you're both writers, write each other a letter.

Hire a skywriter to write "Will you marry me?" in the sky.

Hide the ring in a piece of cake or a bottle of champagne.

Take her on a scavenger hunt that ends with the proposal.

Tell her how much you love her and why you want to spend the rest of your life with her.