Be to the point
Be frank and precise on who you are, what you want and why you should join the event. Make sure the reader gets interested in who you are, and would like to find out more about you, instead of presenting an overkill of information and making the reader bored out of you.
Demonstrate how you are concerned about the world around you and how you would like to act upon it, or show how you would like to transfer you social awareness upon others. Thus exhibit how you could be, or wish to be of service to others.
Just write as if you would speak. Don’t throw in corny lines, don’t use too many business terms or abbreviations, don’t copy texts and above all don’t be afraid to show your true colours. Know that we are looking for social leaders, not spineless conformists.
However you can be proud of your achievements, let the CV speak for itself. Focus more on explaining us on what thrives you and what concerns you instead of convincing us why you are qualified to take part in our event. In the worst case, if you get declined for participation, be courteous, as there might be chance that you will get a call later or may participate in another event.
Be serious (but smile)
Take into consideration that time and effort is made to take your application in to consideration. So make sure that the English is good and the arguments you make are concise and that you look splendid in your video application. But then also, don’t always take yourself too serious.. As a sincere smile can sometimes work even better than the strongest argument.