I'm not sure byu is absolutely looking for candidates who they think will succeed at BYU. I think they are also looking for certain types of candidates...not just those with the best chances to succeed...but those who they think "deserve" to get in. BYU has moved to a fairly homogeneous model ( you can look up the stats on their web site to see the percentage of students who,are seminary graduates, etc).

So just be yourself and be the best you can be, whether it's at BYU or somewhere else.