Comma in direct address

It is not a complete sentence. You can say  Mary, I wish you good luck. "Always use a comma when directly addressing someone/something, regardless of whether the direct address is at the beginning or end of the sentence."

We would often use "Good Luck" followed by a preposition.  

 There are other various phrases using good luck + preposition

1. " Good luck on the exams" 2)" Good luck on the wedding " 1) " I would like to wish you good luck for the new year"