How to write a Best Woman speech?

I’m chief bridesmaid to my oldest school friend in June and am really looking forward to it.

The bride’s father will not be attending the wedding as he holds a lot of bitterness towards his children after they sided with their mother when she left him after many years.

The upshot of this is her brother is giving her away, but he is not looking forward to making his speech and the shorter it can be for him the better. With this in mind they have asked me to make a ‘best woman’ speech.

I’m fine about doing it but don’t know what I should say!