There are samples and things here:
Out of every one of my past career interests and ideas, the one has always stuck is commercial aviation; I have always been interested in it!
This sentence has, IMO, some mistakes in it and I don't like the use of the exclamation mark in an essay at all:
Of all my previous career interests and ideas, the one that has always stuck is commercial aviation, which has always fascinated me.
Or something like that. It needs careful proofreading as such an essay should have no mistakes at all.