Your style: are you a Steady Eddie or a Bonkers Billie?
Your memory: can you commit the key traps and variations to memory?
Your study time: can you find and absorb what you need to play this system well?
Your aims: are you trying to get a playable position? are you trying to
set your opponent problems, so they make a mistake? are you inviting
your opponent to waltz with you blindfold on the edge of a cliff? are
you trying to lure them into unfamiliar territory, or a trap?
I have been writing about the games from the U14 county team events for
many years now (12) and often end up saying the same things. This year
we had a couple of particularly clear examples of "the most important
mistake in chess" ... which is: