Have to give a best man speech at my brother's wedding in less than a month

Have to give a best man speech at my brother's wedding in less than a month I am so nervous that I am going to stutter and embarrass myself in front of 270 people. I have never done anything remotely similar to this before. In college for presentations I used to fake sick so I could later just present in front of the teacher alone. I am being instructed to keep it short, which is helpful, but could anyone share tips on what they did / how I can prepare (besides taking a shot or two, and maybe a beta blocker haha).