It's a positive and encouraging phrase, commonly used to praise someone's efforts or achievements.
Here's a breakdown of the phrase:
* よく (yoku): means "well" or "good"
* できました (dekimashita): is the past tense of "dekiru" (to be able to do), meaning "was able to do" or "did"
Therefore, "yoku dekimashita" literally translates to "You were able to do it well".
Here are some other ways to say "Good job" in Japanese:
* よくがんばった (yoku ganbatta): You worked hard
* 素晴らしい (subarashii): Amazing
* 上手 (jōzu): Skillful
The choice of phrase depends on the context and the level of praise you want to express.