This is the 10829th most frequent Polish word.
dziennikarskich
Relating to journalists or journalism.
The word 'dziennikarskie' is used as an adjective describing 'osiągnięcia' (achievements), indicating their nature or field is related to journalism.
Ona zdobyła nagrodę za swoje dziennikarskie osiągnięcia.
She received an award for her journalistic achievements.
The word 'dziennikarskich' is modifying 'technikach' (techniques) in an instrumental case, connecting the techniques to the domain of journalism.
Kupiłem książkę o technikach dziennikarskich.
I bought a book about journalistic techniques.
Here, 'dziennikarskich' is used in genitive plural construction to describe 'sukcesów' (successes), indicating they pertain to journalism.