If you're the second to go, it may be harder to win the game. If your opponent takes the center space, counteract that by placing your letter in a corner. If your opponent takes a corner space, take the middle space. This will force a draw in both cases.

Is it possible to win going second in tic tac toe?

As you know, tic tac toe is a solved game that end in a tie with optimal play. And it's too short to really get any initiative as the second player, even for children. Going second there is no way to force a win without 2 misplays from the first player.

How do you guarantee a win in tic tac toe?

Most experienced tic tac toe players put the first "X" in a corner when they get to play first. This gives the opponent the most opportunities to make a mistake. If your opponent responds by putting an O anywhere besides the center, you can guarantee a win.