One of the best ways to get out of a bad habit is to do the exact opposite to the point where it feels totally unnatural. That's usually the point where you'd like to get to. So for example, if you walk with your toes pointing inwards and you'd like to retrain yourself to walk with them pointing straight and forward, you need to consciously turn your feet to the point where you THINK that you're turning your toes out. In fact, when you look down, you'll find that they're pointing forward.
Same with changing a bad golf swing. Let's start with the setup.
The first thing to be aware of is your setup. Firm up your grip, aim to the right of the target and position the ball back in your stance. Obviously you'll only do this extreme opposite for a while until you hit the ball straight, then you get back to a more traditional setup.
Secondly, you need to swing from the inside so the ball starts to the right of your final target.
Thirdly, slightly close your clubface when connecting with the ball by snapping your wrists through impact.
And the final point: get some advice on buying clubs that promote a draw rather than a slice. Any good golfing equipment outlet should be able to help you with this.
Give this some time. Good habits take a while to establish themselves, and likewise, bad habits take equally as long to get rid of!
