Stop playing and think out a plan.With a notebook write Prinplup and all the moves of Prinplup and write in order what one is first or how many times to use the move to defeat her.
Catch more pokemon, always use the 6 slots. ALWAYS. level up Geodude (not sure why you have one, there not great). use potions, berries etc. get a shinx, starly and if you can, get a fire pokemon.