Good association is most important. Associate with people who are pure in their actions. Such persons will give good guidance. By associating with them, you will also develop good qualities.
“Even a moment’s association with a pure devotee cannot be compared to being transferred to heavenly planets or even merging into the Brahman effulgence in complete liberation. For living entities who are destined to give up the body and die, association with pure devotees is the highest benediction.” (Srimad-Bhagavatam 4. 30. 34)
A moment of bad or inappropriate association can easily ruin your whole life.