Try thinking about it in these terms. Your ball flight is determined by only 2 things. That is, the clubhead's face position and path at impact.
FACE - This is the angle or position of the clubhead at impact. This will
determine the initial direction that the ball travels.
PATH - The path is the direction that the clubhead is moving toward the target on the forward swing. It is the path of the clubhead at
impact that puts spin on the ball. The spin will cause the ball
to curve during its flight.
So, with that in mind, lets focus on PATH. When your ball slices, the path of your clubhead is cutting across your intend line of flight. Furthermore, the clubhead is coming from the outside to the inside. To make the ball stop slicing, we must get the clubhead to swing in the opposite direction. Which is, to swing from the inside to the outside. In order to accomplish this, try focusing on the inside corner of your ball. Then, just try to hit that corner with the clubface.
This thought about path and focusing on which part of the ball to hit, will get the clubhead swinging in the right direction. You can do it! Just remember, FACE and PATH. Hit the inside corner of the ball. Good Luck!