Careful; meticulous — doing something thoroughly and with close attention to detail.
入念に準備をして試験に臨んだ。
I prepared meticulously and took the exam.
彼の入念なチェックのおかげでミスを防げた。
Thanks to his meticulous checking, we were able to avoid mistakes.
入念な下調べが成功の鍵だ。
Thorough preliminary research is the key to success.