Dissertation acknowledgements
The acknowledgements are the only part of the dissertation where you are writing as yourself instead of the Impartial Professional Narrator.  Just relax and be honest.  (Yes, that can be hard, especially after so many years of writing as Impartial Professional Narrator.) 

Don't worry too much about writing it the right way.  Just be yourself.  Of course your acknowledgements will sound trite to the average reader, but you're not writing to the average reader; you're writing to your mentors, colleagues, friends, and family, who will value the sentiment far more than the specific words.

And don't forget to send a copy of your dissertation to each of the people you acknowledge, especially your family.