Stick to the topic, and don't go meta. Leave out things like "when I was preparing to submit this talk proposal" or "as I was creating the slides for this talk." Talk about the topic, don't talk about the talking.
Know the language and culture of your audience. If it's a mixture of people who don't speak English (or whatever language) as their first language, take care to avoid colourful metaphors that make sense to a native speaker but which confuse non-native speakers. I've confused people with expressions like "inside baseball" or reference to "Goldilocks values" (not too much, not too little). Good metaphors are valuable. Metaphors that depend on too much cultural context are unhelpful.
Know the language and culture of your audience. If it's a mixture of people who don't speak English (or whatever language) as their first language, take care to avoid colourful metaphors that make sense to a native speaker but which confuse non-native speakers. I've confused people with expressions like "inside baseball" or reference to "Goldilocks values" (not too much, not too little). Good metaphors are valuable. Metaphors that depend on too much cultural context are unhelpful.