In Gravity Gammon you have to consider which of your play pieces you want to move. Their weight is important. It is also important to be able to control the squares connected to a bridge. If you can knock out one of his play pieces try to block his entrance to the game by placing two or more play pieces on the squares in front of him.
And finally – be careful in the use of the doubler dice.
Have a nice time playing Gravity Gammon– and remember: You will surely become better and better the more games you play.