Sambo,
Similar to Str12 managed to blag a week on HMS Iron Duke and a week on an ex RN minesweeper (Marine Society I think) through the Careers Office. Excellent prep for AIB and gives you a taste of what life at sea is actually like. Remember at AIB they are looking for 'well rounded individuals'. This does not mean being chubby! Have interests, hobbies, ambitions and some knowledge of the RN. One guy on my board failed even though he was a walking encyclopedia of RN info. Also interact with your fellow boardees. You are being watched more than you think and they are looking for someone who will join in, get on with people and not just sit in a corner on their own. If over the age of 18 the Lord Nelson is a good oppurtunity for socialising with the other candidates but go easy as staff drink there and hungover attempts at Leadership tasks are not appreciated. Also remember not to bullsh
t. The Board will pick this up and rip into it, knocking any confidence you have and exposing yourself to doubts over integrity.
Apart from that try to relax and come across as the normal person you probably are.
Good luck.