Two of the most important traits of a wedding toast, including the toast to the groomsmen, are humor and warmth. Other very important tips are to stay sober and stand up straight.
When writing a toast, start with a humorous anecdote or story, and then be sure to thank the groomsmen for taking part in this happiest and most important of days. Be sure to adhere to the three Bs of speeches: Be brief. Be brilliant. Be seated. Before the special day, practice the toast again and again until all the bugs and hesitations are worked out, practicing a few times in front of a live person. Never read from a piece of paper or card. Finally, keep it G-rated in respect to the children and grandparents often present at weddings.