Learning to say “no” is one of the Golden Rules of time management. In 80% of all cases, you won’t need to say “no.” Offer a “conditional yes” instead – “I’d be happy to help you” – and then refuse politely and explain why – “but I really must finish this.” Don’t let the person leave empty-handed: “I have a suggestion… Have you thought about… Next time…”
Suggest two realistic options and let the person choose which one suits them best.