First adopt the eastern forehand, then move your hand anti-clockwise around the handle, tucking your thumb underneath and making sure your palm is more on the top. Wrapping your thumb around the handle like this, allows the grip to be more firm. However, you must make sure that your fingers are not too close together.

Many players adopt a two-handed backhand for extra strength. Adopt the same grip, bracing your second hand adjacent to the first.