Reserve and use enough preparation time
Although the allotted time for your presentation will be something between 4 and 6 minutes, it will take a significantly larger amount of time to plan, draft, practice and finalize it. You should not wait for the last day but make sure you start as early as possible.
Pick the right combination of things to talk about
Although the icebreaker is typically about you, you will find out that having to present something about yourself in front of an audience is not that simple. You will need to consider what are the aspects of your life and your personality you will want to discuss about and how they make sense when you put them together into a speech. Make it interesting, funny and don't be too afraid of opening up beyond the typical lines about yourself you use when you meet someone.
Consider using visuals, like photos
I used a PC to project photos of my kids, wife, etc. as a support for my presentation. I felt that I would not have had enough time to tell enough about people who are important to me and that using photos I would have been able to bring the message to the audience. This worked out well based on the feedback but it complicated a bit the delivery as I had to control also the photo flow plus I had little time to set up the PC once my time started. I was also told that I was blocking part of the view for some of the audience. In summary, make sure you carefully check your setup before the start of the meeting.
Prioritize few topics to reserve enough time for them
Based on my speech but also on that of some of my peers, I can say that often it is better to select a few key topics to talk about and dive deep enough into them in your presentation. Having too many items will force you to rush through all of them and at the and you will leave your audience with basically nothing more than a list. Leave out less important topics and consider using them for your next speeches.
Create a script, but do not use it at the speech.
I did write a script for the things I wanted to talk about. It was a very useful exercise because it helped me with thinking more carefully of what to say, how to say it and what flow to use. I used it to practice the speech and it helped me realize that initially I had planned for too much to be said. However, I now realize I should have left it behind when keeping the speech. After all the icebreaker is about you so you should know what to say. At the beginning of the speech I found myself paying too much attention at saying the same words I had in the script instead of the overall aspects of the performance. I guess it would have been enough to have some key points written down just as a reminder of the flow. I will try that next time.
I will stop here. In the toastmasters kit you will find other type of hints that you should consider. Above all, try to be as relaxed as possible and do not take it too seriously. This is your first speech, you are there to learn and have fun.