The tragedy of losing your other at 11 will certainly not lead to refusal.
Put yourself in their shoes. They need to be convinced that you are a worthy investment. They want to see character, understanding, energy and ambition. Bone up on world affairs, if you are in to sport you can talk about that. Any travel would be of great benefit and your plans to better yourself i.e Duke of Edinburghs etc. Most of all, be yourself. They can spot a phoney.
Best of luck to you.