Better Presentations : Speak in the intersection of your strength, passion and audience's interest

After many presentations I have done I realised that most presentations would improve if you keep in mind a simple idea: to speak in the intersection of your strength, passion and audience's interest. If you talk about something you are not really good at, you lack credibility. If you talk about passion only, you won't satisfy listeners' need for logic. But when you talk about something you are great at, it's usually something you are passionate about and it might be adjusted to the needs of your audience easily.