The word "conscientious" means being very careful, thorough, and diligent in doing something. A conscientious person pays close attention to details and tries to do their work or duties well and responsibly.

Example:

• She is a conscientious student who always completes her assignments on time.
• He approached the project with conscientious effort to ensure everything was perfect.

If you want, I can give you synonyms or use it in more sentences!