The technology will not work.
There is a good chance this may happen, but if you prepare alternatives ahead of time you will be able to deal with any setback. Bring handouts, save your presentation to a portable drive, or you could even find an overhead projector. The key, though, is to have a good speech memorized that is just as effective without visuals.
The audience is uninterested or dislikes me.
Almost always the audience wants to see you be successful. Though some audience members may come across as abrupt or unfriendly, it may not be at all related to your speech skills.
I can't come up with an interesting topic.
Each person has a unique perspective on the world with valuable information to present. If you choose a topic that interests and excites you, that enthusiasm will come across as you talk about the topic and will engage the audience. You can also craft the speech to be more relevant to your audience, using examples they can relate to, which will keep their attention.
I'll forget everything in the speech.
The best way to counteract forgetting parts of your speech is to practice. And practice. And practice more. Once you have the speech outline memorized, you'll be able to deal with any moments when you get lost or diverted in the delivery. If you do get stuck - stop, breath, take a moment to look over your notes, and continue.
I can't keep track of time while speaking and I'll finish too early or too late.
Again, practice. The only way to meet the requirements of the speech is to practice thoroughly.
I get nervous in front of a group and talk too quickly or quietly.
Talking too quickly or quietly can be a problem in front of a group. If you breathe deeply you will minimize your anxiety and better prepare yourself to speak loudly and clearly. Try practicing in a large room and projecting your voice to the very back. Remember to add pauses or moments of silence in your speech, which can be effective tools to emphasize a point.
Know your fears - make a list of those things that make you feel anxious or fearful, then make another list with all of the ways you can deal with those fears.
Take Deep Breathes - when you practice your speech, also practice taking deep, slow breathes. This will help you calm down and speak more clearly.
Practice, Practice, Practice - practicing what you will say will help you feel prepared and confident before your speech.
Imagine Yourself Succeeding - what would a successful speech look like for you? Create a mental picture and practice to achieve that visualization.
Scope Out the Space - take a look at where you will be speaking ahead of time, learn as many details as possible: will you be on a stage?, behind a podium?, is there a clock?, what is the technology like?
Exercise to Calm Down - take a quick walk, stretch, or climb stairs to reduce any pre-speech jitters and burn off excess nervous energy.
Take Care of Yourself - get a good night's sleep and eat a healthy meal before your speech. Follow any normal routines before the speech. Avoid coffee if you tend to get anxious.
Don't Be Focused on "Perfect" - there is no such thing as the perfect speech, since there is always room to improve. Look at any mistakes you make as opportunities for improvement in the future.