The aim is to end up with more counters/stones than your opponent, sometimes easier said than done...

The trick is to control the board, but to do this you have to control the central stones and let your opponent take the outer ones.

By doing this you limit their moves and if you do this well they will only have 1 or two possible moves making it easier for you to force them to place a stone next to the corner for you to take the edge of the board.

Ignore the stone count during the game, it's the end result that matters