There are some questions you need to ask yourself once you decide that you want to speak. Only by answering these questions, and questions of this sort, will you be able to force yourself to focus in the direction that will be most effective in gathering content.
What type of speeches does this specific audience, or this type of audience, appreciate most?
Is the purpose of your speech to inspire? educate? entertain? inform? motivate? persuade? Once you know the purpose of your speech, you can now gauge what you need to achieve the desired results…
Who are the three most important people or types of people that you care will be happy with your message? What type of message would those people appreciate the most?
What troubles the people you are speaking to? What is on their mind? What are the problems that they are dealing with that you dare to attempt to solve? Or if you do not have solutions, in what way can you bring a positive, comforting light to what they are dealing with?