This is the 16442nd most frequent Russian word.
руководствуюсь
"I am guided by" or "I follow."
Here, 'руководствуюсь' (I follow/adhere to) is used to indicate that the speaker relies on a principle ('здравый смысл' - 'common sense') as a guide in their decisions.
Я всегда руководствуюсь здравым смыслом в принятии решений.
I always follow common sense when making decisions.
In this sentence, 'руководствуется' (is guided by) expresses that the subject relies on their personal principles ('собственными принципами') regardless of external opinions.
Он руководствуется собственными принципами, несмотря на критику.
He is guided by his own principles despite criticism.
The word 'Руководствуясь' (following/being guided by) shows that the action (completion of the project) was done under the guidance of specific advice ('вашими рекомендациями').