Party speech

Hi!

Tomorrow I am suppose to hold about a speech in any occasion. It could be a wedding, a party or something similar. This is for a schoolproject so I will get a grade at how good i speak.
Now, since I have never done anything like this before i don´t know how I will start the speech, finish it, or even what I should talk about.

I would really appreciate if someone could help me and give me some tips on what i can say and so on.

Thanks in advance

edit; sorry, i just saw that there was a speech category.