Reversi is one of those games that's easy to play - but not necessarily easy to play well. Reversi is a strategy based game and players need to take advantage of all of them, with increasing capabilities as their skills develop further, in order to have a better chance at defeating their opponents.
Reversi Strategy #1 - Reversi Corners
Corners are a good strategy to use because once they have been played, they can't be flipped again, and when a player has control over one of more corners they can anchor pieces that go along the edges of the Reversi board, making it impossible to flip those as well. Using corners gives players more opportunity to take control over the Reversi board.
Reversi Strategy #2 - Reversi Mobility
The easiest strategy in Reversi is to set your opponent up so they are forced to play moves that make them give up on their good moves. Try to make moves that will stop your opponent from being able to make moves that are to their advantage. The fewer moves available to your opponent, the sooner they will have to move a piece to an area that he/she doesn't want to play. Try to get your pieces in the middle of the board with your opponent's pieces around you - with this setup it will be easy to predict which moves the other player might make and can help you shape your own strategy further.
It's also a great strategy for you to play minimum piece strategy - this can be used when you believe the moves available to you and the other player are about equal.
Reversi Strategy #3 - Reversi EdgesM
Playing pieces around the edges can be a good strategy, because they can't be flipped as easily, however, it does affect the moves available on the board which can work against you. By playing edges early in the game in Reversi, you might later be forced to flip more pieces than you want to and open up additional moves to the other player - which is never something that you want to do! For example, if you play the X-square (the square diagonal from the adjacent corner) early in the game, it's usually a recipe for failure. Unless you are a very experienced Reversi player, avoid playing at the edge early in the game at all costs because the risk is high and there's a great deal of additional strategy and evaluation involved with edge play.
Reversi Strategy #4 -Reversi Parity
Later in the game in Reversi, players may gain control of different sides of the board. Count whether there is an odd or even number - if it is odd, try to force your opponent to play outside of their area. Do this by playing in that area as soon as there are an odd number of squares available, and you might even be able to get your opponent to play one of the more undesirable squares on that side of the board.
Reversi Strategy #5 - Look a head and End game
In Reversi, don't just look at what's happening on the board at any given time, try to look ahead and predict what your opponent will do next, and try to determine how you will respond to those moves. Looking in the long-term in Reversi, will help you improve your strategy and defeat your opponent!
The End Game is the last 20 moves in the game, and there are some special techniques that can be applied. In the last stages of the game, just try to look at how you can gain the best control over the final outcome!