Ask HN: Gin rummy strategies

Hi HN, I am having AI build me a local Gin Rummy trainer and it cannot figure out medium and hard bot strategies, they keep losing to easy! The point of this is to help me learn so I don't really know how to advise it on strategies. Right now it's just looping through tests and modifying but it keeps not improving. Does anyone have any recommendations or guidance for strategies I could suggest to it?