This is a documentation for Board Game Arena: play board games online !
Tips yatzy
N.B. You choose the dice to re-roll, instead of choosing the dice to keep. Not only is that backwards from every other implementation I've ever played, it is backwards to how you think about your turn.
I realize this isn't exactly strategy, but on the off-chance somebody reads this who hasn't played the game before, it might save them ruining their very first turn of the game.
There is an online application that allows you to compare your moves with those of a computer playing optimally (i.e. making plays that are most likely to score you the highest overall, in the largest number of possible scenarios). Try using it and see if you can improve your thinking.
Another app on that same website lets you play through an entire game of Yahtzee and get all of it analyzed afterwards. Here are the instructions on how to read the analysis.