The formula for a memorable wedding toast is simple: two minutes, one story, one turn. The two-minute rule is not arbitrary; it is the length at which an audience stays with you without drifting. Any longer and you lose the room. Shorter is fine if you have said what needed saying.
The one-story rule keeps you focused. Pick a single anecdote that reveals something real about the couple or your relationship to them, and tell it well. Anecdote beats generalisation every time: "I remember the first time Sarah called me about James" beats "Sarah has always been the most generous friend." Specific details, ideally one or two of them, lock the toast in the audience's memory.
The one-turn rule is about structure. Set up the story, land a moment that makes the room feel something (laugh, catch their breath, tear up briefly), and then turn the toast toward the couple and the wedding day you are all at. Every good toast has this arc: a beginning (you/them in the past), a middle (the anecdote), and an end (them here now, and a wish for the future).