If you make a game "computer vs Human" what are some code you can write for "computer" to win instead of playing randomly?

Answer 1

depends on the code

Answer 2

You might try to teach it. Or to apply scaling/grading to all possible decisions - awarding positive moves and punishing bad ones.
In checkers or chess a good move is a one that does not put you in an immediate loss situation in the next move. A bonus here, if by this move you make your opponent lose a pin, yet another bonus if you make a check (or reach a queen in checkers). And so on...