You will always feel more uncomfortable speaking in front of people you don't know than people you do know - it's just human nature! Strangers can be a lot more intimidating because you just don't know what to expect. So why not learn as much as you can about your audience before you begin?
How many people are you talking to?
First of all, how many people will be in your audience? Visualize the size of the audience, where you will stand and how you will interact with them. What will their seating arrangement be like? Will they be at a boardroom table, in a large auditorium, at numerous circular tables, or in rows? Keep these things in mind when you design your visuals and plan interactive activities.
What are the demographics of your group?
Keep your content relevant to the demographics of your group. How old are the people in your audience? Are they mostly men or women? What are their ethnic backrounds? Your material should be as fine-tuned to this audience as possible so that they find your talk relevant, up-to-date, interesting and educational.
How do you get this information?
Many speakers send a pre-talk questionairre to the event organizer or corporation with all the information they would like to know before the talk. Don't be afraid to do this. Organizers are happy to see that you are customizing your talk to their group. If your speaking at a meeting at work it's a little bit easier to think about audience factors since you probably know your colleagues fairly well.
Related article: The Top 5 Things to Know about Your Audience - Before You Give Your Talk!