The key to effective speech writing is to KNOW your audience. Once you know who your audience is you can begin to make an outline. The first step is to turn off your computer and start to brainstorm. Write down on a piece of paper:

Who:  Write down as much as possible about the people who will be attending the speech.

What: Write down the title and using your notes from the who and what you have been asked to speak about, will give you ideas on how to specifically meet and serve the interests of your audience.

How: There are two important questions here:
How long the speech will be?

How will the speech be told?
Will it be a persuasive speech?
Will it be a humours speech?
Will it be a speech with photographs?
Will I use power point? 
Again, it's important to keep your audience in mind.

When: The date, time, day, and season will have an impact on your audience. If possible a mid-morning or afternoon timeslot is ideal. Attention spans are not at their best when people are hungry or tired.

Where: It's best to arrive early and make sure eveything is in working order. Even the most rehearsed speeches can fail because of insufficient thought in the where.
Where will I be in relation to the audience?
Will they see me easily?
Will they hear me easily?
Do I need a microphone?
Is there a place to put my notes if I’m using some?
Are there power points if I want to use any electronic devices?
Do I have to provide everything I want to use (e.g.: computer, screen…)?

Now it's time to put it all together. Remember this is an outline. Write down your answers and let them be your guide.

Good luck and happy writing!