I'm not quite sure how to start it when I'm standing in front of everybody. I tried searching on Google but nothing came up under groomsmen that helped me. Any help is greatly appreciated.
Also an example would be great.
Definitely keep it short. Having a long speech is not what people want to hear. I would consider adding a little bit of humor to your speech. It is also always a good idea to briefly discuss a special memory that you have of the bride or groom. At the end of your, make sure you wish them a lifetime of happiness.
In addition to the excellent advice above, keep your speech short! That will make it easier on you and the guests. I know that it's tempting for many speakers to wax eloquent, but a reception is not the place to do it. If you can include humor, that's always great too.
Well, I think the very best wedding speeches are those that come from the heart, do not make any false pretenses, and are spoken in love and laughter.
That said, when you get the microphone, you could start by saying, "I was actually so nervous about this speech that I went to the internet looking for 'speech starters.'" Not to make fun of you, but I love that you did that, and I really think your brother and family will find it endearingly funny. If you can get a couple laughs at the beginning, you will feel more at ease. Letting the crowd know you are a bit nervous but still in it - they'll love you.
I also encourage you to make it all about your brother. Focus on the things you love about him that will make him a good husband/father/whatever... people love hearing good things about themselves and we don't have many opportunities in our culture that call for that kind of flattery. Wedding toasts are one such occasion that call for admiration and best-wishes. Most people spice them up with a few sentimentally funny stories about the bride or groom - just to keep them humble, but ultimately end on a postive note.
Not that I'm a critique of wedding speeches... just be yourself (cliche as that might sound) and really, you'll do fine.